Improving Informed Consent Form Readability: A Data-Driven Guide for Clinical Researchers

Robert West Dec 02, 2025 380

This article provides a comprehensive framework for researchers and drug development professionals to enhance the readability and comprehension of informed consent forms (ICFs).

Improving Informed Consent Form Readability: A Data-Driven Guide for Clinical Researchers

Abstract

This article provides a comprehensive framework for researchers and drug development professionals to enhance the readability and comprehension of informed consent forms (ICFs). Drawing on recent global studies and institutional successes, it outlines the proven strategies, from using plain language and achieving target readability scores to implementing validation techniques like teach-back. The guide addresses the documented prevalence of poorly readable ICFs and offers actionable solutions to meet ethical standards, regulatory requirements, and improve participant understanding in clinical trials.

The Readability Crisis in Informed Consent: Why It Matters for Ethical Research

Defining Readability and Its Direct Impact on Participant Comprehension

Frequently Asked Questions (FAQs)

Q1: What is "readability" in the context of an Informed Consent Form (ICF)? A1: Readability is a quantitative measure of how easy a written document is to read and understand. It is typically assessed using mathematical formulas that evaluate factors like sentence length and word complexity, often resulting in a score or a US school grade level [1]. For ICFs, the goal is to achieve a reading level that allows the target population to comprehend the information without undue difficulty.

Q2: What is the recommended readability grade level for an ICF? A2: Major institutions like Johns Hopkins Medicine and the NIH recommend that the reading level of an ICF should be no higher than an 8th-grade level [2] [3]. This ensures the document is accessible to a wide audience, as about half of US adults read at or below the 8th-grade level [3].

Q3: Why is readability so crucial for participant comprehension? A3: Complex and difficult-to-read ICFs directly hinder a participant's understanding of the research. Evidence shows that participants who find the ICF difficult to understand are more than twice as likely to drop out of a clinical trial [4]. Furthermore, inadequate comprehension can lead to participants signing the form without truly understanding key research concepts like risks, randomization, or their rights [3].

Q4: My ICF is for a highly technical study. Is it possible to meet the 8th-grade reading target? A4: While challenging, it is a critical goal. The IRB recognizes that some consent forms are of such a technical nature that it may be difficult to maintain an 8th-grade level. Investigators are encouraged to discuss any problems in achieving this with their IRB or consent form specialists [2]. Using plain language principles is key to simplifying complex information without sacrificing accuracy [5].

Q5: How can I check the readability score of my consent form? A5: You can use the built-in tool in Microsoft Word:

Go to File > Options > Proofing.
Check the box for "Show readability statistics."
After running a spell check, the tool will display the Flesch-Kincaid Grade Level and other metrics [5] [2]. Other free online readability checkers are also available [5].

Troubleshooting Guides

Problem: My ICF's readability score is too high (above 8th-grade level).

Symptom	Potential Cause	Solution
Long, complex sentences	Use of passive voice and multiple clauses in a single sentence.	Break long sentences into shorter, one-thought sentences. Use active voice (e.g., "We will measure your blood pressure," not "Your blood pressure will be measured by us.") [5] [2].
Difficult vocabulary	Use of medical or scientific jargon.	Replace jargon with simple, plain language words. Use words with fewer than three syllables where possible (e.g., "use" instead of "utilize," "about" instead of "approximately") [5] [2].
Dense text blocks	Long paragraphs without visual breaks.	Keep paragraphs short and limited to one idea. Use bulleted or numbered lists when presenting three or more items [5]. Use margins of at least 1 inch and a left-justified, right-ragged format [5].
Poor participant identification	Use of third-person language (e.g., "the participant").	Use the second person "you" to increase personal identification and connection with the material [2].

Problem: Participants do not seem to understand key risks and side effects.

Symptom	Potential Cause	Solution
Participant confusion over side effect likelihood	Using vague verbal descriptors (e.g., "common," "rare") without numerical context.	Use numerical information to describe frequency. Pair verbal descriptors with absolute frequencies (e.g., "5 out of 100 participants"), percentages, or frequency bands (e.g., "may affect more than 1 in 10 people") to improve accuracy [4].
Important information is being missed	Failure to visually emphasize critical points.	Highlight important points using bold or italics, but avoid using ALL CAPS or multiple formats at once, as this reduces effectiveness [5] [2].
Inadequate understanding of complex concepts	Assuming technical terms are understood (e.g., "randomized," "placebo").	Define all research-specific concepts when first introduced. For example: "A placebo is an inactive substance that looks like the study drug but contains no medication" [2].

Quantitative Data on ICF Readability

Table 1: Readability Standards and Formulas

Formula	Target Score / Level	Interpretation
Flesch Reading Ease (FRE)	60-70 (Standard) / 70+ (Easy)	Score of 0-100; higher score = easier to read [5] [1].
Flesch-Kincaid Grade Level (FKGL)	≤ 8th Grade	U.S. grade level needed to understand the text [5] [1].
SMOG Index	≤ 8th Grade	Estimates years of education needed to understand the text [1].
Gunning Fog Index	≤ 8th Grade	Estimates years of formal education needed to understand the text [1].

Table 2: Empirical Evidence on Readability Impact

Study Focus	Key Finding	Implication
General Health RICFs (Tanzania) [6]	80.5% of forms were difficult to read, requiring a US grade 10 level to understand.	A significant global gap exists between recommended and actual ICF readability.
Gynecologic Cancer Trials (USA) [7]	Mean reading grade level for ICFs was 13th grade, far exceeding the 8th-grade recommendation.	Readability remains a pervasive problem even at major US cancer centers, potentially creating enrollment barriers.
Comprehension Experiment (USA) [3]	Participants performed significantly better on a simplified ICF (FKGL 8.2) vs. the original (FKGL 12.3).	Direct evidence that improving readability through plain language revisions directly enhances participant comprehension.
Institutional Template Use [8]	ICFs created with a plain language template averaged an 8th-grade level, vs. grade 11 for those without a template.	Using institutional plain language templates is an effective strategy for systematically improving readability.

Experimental Protocols for Readability Improvement

Protocol 1: Implementing a Plain Language Revision

Assess Baseline: Run the initial ICF draft through a readability checker (e.g., in Microsoft Word) to establish the baseline Flesch-Kincaid Grade Level [5].
Apply Simplification Techniques:
- Replace all medical jargon with plain language equivalents [5].
- Break long sentences into shorter ones, aiming for one main thought per sentence [5] [2].
- Change passive voice sentences to active voice [5].
- Use "you" to address the participant directly [2].
Format for Clarity: Introduce bullet points for lists, increase white space, and use a 12-point sans-serif font like Arial or Calibri [5].
Validate and Test: Have a layperson review the revised document and answer comprehension questions [5]. Re-check the readability score to quantify improvement.

Protocol 2: Evaluating the Impact on Comprehension

Design: Create a between-groups study where one group receives the original ICF and another receives the simplified ICF [3].
Materials: Develop a comprehension test with true/false or multiple-choice questions based on key information in the ICF (e.g., purpose, procedures, risks, rights) [3].
Procedure: Recruit participants representative of the study population. After they read the assigned ICF, administer the comprehension test.
Analysis: Use statistical tests (e.g., a t-test) to compare the mean comprehension scores between the two groups. The study by Best et al. (2024) used this method and found a statistically significant improvement in comprehension for the simplified form [3].

Readability Improvement Workflow

The Scientist's Toolkit: Essential Reagents for Readability

Table 3: Key Research Reagent Solutions for Readability

Tool / Resource	Function	Example / Source
Microsoft Word Readability Tool	Provides automated Flesch-Kincaid readability scores during spell check [5] [2].	File > Options > Proofing > Check "Show readability statistics."
Plain Language Guidelines	A set of writing rules to simplify syntax and semantics, replacing complex terms with common words [5] [3].	Use "about" instead of "approximately"; "use" instead of "utilize." [5]
Lay Reviewer	A non-expert who validates the clarity and comprehensibility of the ICF [5].	A colleague or individual from the community not involved in the research.
Institutional Plain Language ICF Template	A pre-formatted template designed to guide writers in creating consents at the target grade level [8].	Often provided by IRBs or institutional centers for health literacy.
Readability Formulas	Mathematical models to quantitatively assess text difficulty [1].	Flesch Reading Ease, Flesch-Kincaid Grade Level, SMOG, Gunning Fog.
Large Language Models (LLMs)	An emerging tool to assist in automatically generating and simplifying ICF text while maintaining accuracy [9].	E.g., Fine-tuned Mistral 8x22B model [9].

Frequently Asked Questions

What makes a consent form "poorly readable"? A consent form is considered poorly readable when its language and structure are too complex for a layperson to understand. This is often measured by readability formulas (like Flesch-Kincaid) that analyze factors such as sentence length and syllables per word. Forms requiring a high school or college reading level are problematic, as they fail to meet the recommended 8th-grade reading level [2] [10]. Poor readability hinders comprehension, preventing participants from truly understanding what they are consenting to [11].

Why is the global prevalence of this issue considered "alarming"? The prevalence is alarming because recent, comprehensive evidence confirms that the majority of consent forms are difficult to read. A 2025 systematic review of 26 studies analyzing 13,940 consent forms found that 76.3% had poor readability [1]. This widespread failure undermines the ethical and legal foundation of informed consent, potentially violating participants' rights and autonomy across countless studies and medical procedures.

Are there specific regions or languages where this problem is worse? The problem is global, but research and tools are unevenly distributed. The 2025 review analyzed forms in six languages but found that adapted readability indices were only available for English, Spanish, and Turkish [1]. This suggests that properly assessing and improving readability in other languages may be more challenging. Furthermore, translations of English consent forms are often literal and fail to capture the original meaning, making them even harder to understand [11].

What are the concrete risks of using a poorly readable consent form? The risks are significant for both participants and researchers:

For Participants: They cannot make a truly autonomous decision about their participation. They may not understand the procedures, risks, benefits, or their right to withdraw, leading to uninformed consent [12] [11].
For Researchers & Institutions: This practice exposes the research to ethical and legal challenges. It can invalidate the consent process, damage the credibility of the institution, and in regulated research, lead to non-compliance with regulatory standards [12] [13].

How can I quickly check the readability of my consent form? You can use built-in tools in word processors. For example, in Microsoft Word, you can enable the Readability Statistics feature, which provides Flesch-Kincaid Grade Level scores [2]. The JHM IRB recommends that the reading level should be no higher than an 8th-grade level [2], a standard echoed by other institutions [10].

Troubleshooting Guides

Follow this protocol to quantitatively and qualitatively assess your consent form's readability.

Experimental Protocol for Readability Assessment

Quantitative Analysis (Using Readability Formulas):
- Tool Setup: Enable the readability statistics feature in your word processing software [2].
- Procedure: Run a spelling and grammar check on the complete text of your consent form.
- Data Collection: Record the scores generated by the tool. The most common formulas and their target values are summarized in Table 1 below.
- Interpretation: Compare your scores against the recommended thresholds. A Flesch-Kincaid Grade Level above 8 indicates a need for revision [2] [10].
Qualitative Analysis (Assessing Comprehensibility):
- Procedure: Read the form out loud to colleagues and test it on individuals representative of your target audience [2].
- Data Collection: Use a questionnaire or simple interview to test the participant's understanding of key concepts like the study's purpose, risks, and voluntary nature [11].
- Alternative Method: Ask a potential participant to write the salient features of the study in their own handwriting to ensure key points are focused on and understood [11].

Table 1: Key Readability Indices and Target Thresholds for Consent Forms

Index Name	Applicable Language	Score Type	Target Threshold for Good Readability	Interpretation of Target
Flesch-Kincaid Grade Level [1] [10]	English	Grade Level	≤ 8th Grade	Understandable by ~80% of adults [1].
Flesch Reading Ease [1]	English	0-100 Score	≥ 60	Scores of 60-70 are considered "Standard" or "Plain English" [1].
SMOG Index [1]	English	Grade Level	≤ 8	Considered adequate for most people [1].
Gunning Fog Index [1]	English	Grade Level	< 8	Comprehension is "almost universal" below 8 [1].
Flesch-Szigriszt Index [1]	Spanish	0-100 Score	≥ 51	Easily understandable by the majority [1].
INFLESZ Index [1]	Spanish	0-100 Score	≥ 55	Can be read and comprehended by a large percentage of patients [1].

Guide 2: Implementing a Strategy for Readability Improvement

This guide provides a systematic methodology to revise a consent form and enhance participant comprehension.

Experimental Protocol for Readability Enhancement

Apply Plain Language Principles:
- Use Active Voice: Write "We will send you a summary," not "A summary will be sent to you." [10]
- Shorten Sentences: Divide long, complex sentences into shorter, direct ones [2].
- Simplify Vocabulary: Use words familiar to a non-medical reader and keep them to 3 syllables or fewer where possible [2]. Replace technical terms with lay language (e.g., "study doctor" instead of "principal investigator") [2].
- Use Second Person: Address the reader directly as "you" to increase personal identification [2] [10].
Optimize Format and Structure:
- Implement Key Information First: Begin the form with a concise presentation of the most important information to help a prospective participant decide whether to join [13] [14].
- Enhance Visual Design: Use at least 12-point font, keep paragraphs short, and highlight important points with bold or underline rather than italics or all caps [2].
- Create Modular Consent: Instead of a single "I agree" checkbox, use a structure with multiple checkboxes allowing participants to consent to specific activities (e.g., audio recording, data publication) separately [12].
Validate and Iterate:
- Peer and Lay Review: Have the form reviewed by colleagues and, crucially, by lay persons who can assess comprehensibility [11].
- Usability Testing: Test draft versions with individuals from your intended participant population and make changes based on their feedback [13].
- Employ Teach-Back: The most reliable method to increase understanding is to incorporate a consent process with an extra meeting where participants can "teach back" the information to confirm their comprehension [11] [13].

The following workflow diagram illustrates this systematic approach to creating a readable consent form.

Table 2: Research Reagent Solutions for Consent Form Improvement

Item	Function/Brief Explanation
Plain Language Guidelines [2] [13]	A set of writing principles (e.g., using active voice, short sentences, common words) to make complex information clear and understandable for a lay audience.
Readability Software (e.g., Flesch-Kincaid in MS Word) [2]	A tool that provides quantitative metrics on text difficulty, allowing researchers to objectively assess and target an appropriate reading grade level.
Lay Terminology Glossary [2]	A reference that provides simple, non-medical alternatives for complex technical and scientific terms (e.g., "high blood pressure" instead of "hypertension").
Modular Consent Framework [12]	A structural approach that breaks down consent into specific, granular choices (e.g., separate checkboxes for audio, video, and data use) rather than a single blanket agreement.
Usability Testing Protocol [13]	A methodological process for testing draft consent forms with individuals from the target population to identify points of confusion and improve comprehensibility.
Teach-Back Method [13]	A validation technique where participants explain the study back to the researcher, ensuring true comprehension and not just a signature.

FAQs: Readability and Regulatory Compliance

What are the specific regulatory requirements for the reading grade level of an informed consent form (ICF)?

While regulations like the Revised Common Rule and FDA guidelines state that consent must be in "language understandable to the subject" [15] [16], they do not specify a precise grade level. However, authoritative bodies recommend a reading level between 6th and 8th grade [5] [7]. This is because the average reading level of U.S. adults is at or below the 8th-grade level [15]. Despite these recommendations, studies show that many consent forms significantly exceed this level, with some averaging as high as the 13th grade [7].

Why is improving ICF readability an ethical imperative?

Readability is directly tied to the ethical principle of respect for persons and the validity of informed consent itself. Consent forms written at a high reading level can create additional risks for participants due to a lack of understanding [15]. They may also limit participation from vulnerable populations and those with lower health literacy, potentially exacerbating healthcare disparities in research [15]. A readable form ensures participants can truly make an autonomous, informed decision.

What are the key FDA guidance points on informed consent that relate to readability?

The FDA's 2023 guidance emphasizes that informed consent is an ongoing process, not merely the act of obtaining a signature [16]. Key points include:

Information must be in language understandable to the subject or their representative [16].
Investigator Responsibilities: The clinical investigator is responsible for ensuring legally effective informed consent is obtained and must delegate the consent discussion only to adequately trained and knowledgeable staff [16].
Recruitment Materials: Materials used for recruitment are considered part of the consent process and are subject to IRB review [16].

Does the Revised Common Rule make consent forms more or less readable?

The Revised Common Rule's requirement for a "Key Information" section at the beginning of the consent form is intended to facilitate comprehension by providing a concise summary [8]. Research has shown that with careful plain-language writing, this new requirement can be implemented without degrading the form's overall readability. One study found that forms using an updated template meeting the new rules maintained an average 8th-grade reading level [8].

Troubleshooting Guides

Problem: High Readability Grade Level

Symptom: Your consent form tests at a 10th-grade reading level or higher using tools like Flesch-Kincaid [15] [7].

Solution: Implement plain language writing techniques.

Step	Action	Example
1	Replace jargon with simple, common words.	Use "high blood pressure" instead of "hypertension" [5].
2	Use short sentences with one idea each.	Break long, complex sentences into two or more simple ones [2].
3	Adopt active voice.	"We will measure your blood pressure," not "Your blood pressure will be measured by us." [5].
4	Use second-person ("you") to speak directly to the participant [2].	"You are being asked to participate..." instead of "The subject is being asked..." [2].

Problem: Poor Participant Comprehension

Symptom: Participants struggle to understand the study's purpose, procedures, risks, and benefits, even after signing the consent form.

Solution: Enhance the document's structure and design for clarity.

Step	Action	Rationale
1	Incorporate a "Key Information" section at the beginning.	Meets Revised Common Rule requirement and provides a concise, easy-to-understand overview [8].
2	Use ample white space and left-justified, "ragged-right" text.	Reduces visual crowding and gives readers visual cues, improving readability [5].
3	Use bold or underline to emphasize critical points.	Helps direct the reader's attention to the most important information [5]. Avoid italics and ALL CAPS, which are harder to read [2].
4	Use bulleted or numbered lists for multiple items.	Makes complex information easier to scan and digest [5].

Problem: Low Adoption of Plain Language Practices by Researchers

Symptom: Investigators at your institution continue to submit complex, technical consent forms for IRB approval.

Solution: Institutional implementation of supportive tools and training.

Step	Action	Evidence of Effectiveness
1	Develop and promote a plain-language ICF template.	One academic center created a template with a 5th-grade reading level [15].
2	Provide training to investigators and IRB staff on the use of the template and plain language principles.	After introducing a template and training, one institution saw a 49% template adoption rate within a year [15].
3	Track adoption and readability metrics.	Institutions that implemented a template saw a 658% increase in the number of consent forms written at or below an 8th-grade level [15].

Experimental Protocols and Data

Quantitative Data on Readability Improvement

Table 1: Baseline Readability of Informed Consent Forms (Pre-Intervention)

This table summarizes the findings of studies that established a baseline for consent form readability before any specific interventions.

Study Focus / Institution	Sample Size	Mean Readability Grade Level	Percentage at >8th Grade Level	Citation
Academic Medical Center (2013-2015)	217	10th Grade	89.1% (Estimated)	[15]
Gynecologic Cancer Trials (2017-2022)	103	13th Grade	100% (Estimated)	[7]
Academic Medical Center (Baseline P1)	84	11.1	82.1%	[8]

Table 2: Impact of Plain Language Template Intervention

This table shows the measurable improvement in readability after the introduction of a plain language informed consent template.

Study / Intervention Group	Sample Size	Mean Readability Grade Level	Percentage at ≤8th Grade Level	Citation
Post-Intervention (Overall)	82	8th Grade	Not Reported	[15]
- Template Adoption Group	41	7th Grade	90.2%	[15]
- No Template Group	42	10th Grade	11.9%	[15]
Longitudinal Study (P3 - Post-Template)	57	9.2	78.9%	[8]

Detailed Methodology: Readability Assessment

For researchers seeking to replicate these studies, the following protocol details how to assess the readability of consent forms.

Objective: To quantitatively determine the reading grade level of an Informed Consent Form (ICF) using multiple validated readability formulas.

Materials:

Informed Consent Document(s): Digital text file (.docx, .txt) of the final ICF.
Text Cleaning Tool: A word processor (e.g., Microsoft Word) or script to prepare text samples.
Readability Analysis Software: Examples include:
- Commercial: Readability Studio Professional Edition [7]
- Software Suite: Seven Formulas software (uses Flesch-Kincaid, SMOG, Fry Graph) [8]
- Free Checker: Microsoft Word's built-in Flesch-Kincaid tool [5] or online automatic readability checkers.

Procedure:

Sample Selection:
- For each ICF, select a 600-word sample from the beginning, middle, and end of the document to ensure a representative sample [8].
Text Cleaning:
- Remove bullet points and extraneous punctuation (e.g., periods in "Dr.") that might incorrectly signal the end of a sentence to the software [8].
- Ensure the text flows as plain, continuous prose for an accurate analysis.
Software Analysis:
- Input each cleaned 600-word sample into the chosen readability software.
- Run the analysis using at least three validated formulas, such as Flesch-Kincaid, SMOG Index, and Fry Graph [15] [8].
Data Calculation:
- For each ICF, average the grade-level results from the three formulas to arrive at a single mean readability score [15] [8].
- For institutional assessments, calculate the mean readability score across all ICFs in the sample.

The Scientist's Toolkit: Research Reagent Solutions

Table 3: Essential Resources for Readability and Compliance

Tool / Resource	Function / Purpose	Example / Key Feature
Plain Language ICF Template	Provides a pre-structured form written at a target (e.g., 5th-8th grade) reading level, ensuring regulatory elements are included in an easy-to-read format.	University of Arkansas for Medical Sciences (UAMS) template [8].
Readability Assessment Software	Quantifies the reading grade level of a text sample using validated algorithms.	Readability Studio, Seven Formulas software, Microsoft Word's Flesch-Kincaid tool [8] [5].
Lay Terminology Glossary	Provides plain-language alternatives for complex medical and scientific terms, which is crucial for replacing jargon.	glossaries from Stanford University or the CDC's "Everyday Words for Public Health Communication" [5] [2].
Color Contrast Checker	Ensures that any text, especially in digital consent materials or over images, meets WCAG guidelines for users with visual impairments.	WebAIM Contrast Checker; requires a 4.5:1 ratio for normal text [17] [18].
Institutional Review Board (IRB)	Reviews and approves consent forms to ensure they meet ethical and regulatory standards for the protection of human subjects.	Provides guidance, such as the Johns Hopkins Medicine IRB's recommendation for an 8th-grade level [2].

Troubleshooting Guides

Guide 1: Diagnosing and Remedying Poor Participant Comprehension

Problem: Research participants demonstrate poor understanding of the study's purpose, procedures, risks, or benefits during consent discussions or comprehension questionnaires.

Investigation & Solutions:

Check Readability Score:
- Symptom: Consent forms consistently test above an 8th-grade reading level.
- Tool: Use built-in Microsoft Word readability statistics (Flesch-Kincaid) or free online tools like the Automatic Readability Checker [5].
- Fix: Rewrite the document. Use simple words with fewer than three syllables, active voice, and break long sentences into one thought per sentence. The goal is a Flesch-Kincaid score of 70 or greater, equivalent to an 8th-grade reading level or below [5] [15].
Assess Language & Structure:
- Symptom: Text is dense, uses complex medical jargon, and has long, unbroken paragraphs.
- Tool: Lay reviewer feedback and "Everyday Words for Public Health Communication" (CDC guide) [5].
- Fix: Replace jargon with plain language. Use bulleted or numbered lists for multiple items. Format with left-justified, right-ragged text, ample white space, and a minimum 12-point sans-serif font (e.g., Arial, Calibri) [5] [11].
Evaluate Comprehension Directly:
- Symptom: Participants cannot correctly answer questions about key study concepts.
- Tool: Short, validated comprehension questionnaire administered after the consent process [11].
- Fix: Implement a simplified consent form as a "universal precaution." Studies show this improves comprehension for all participants, regardless of their age, race, or baseline reading skill [3]. Supplement the form with additional informational meetings with a counselor or qualified team member [11].

Guide 2: Addressing Low Enrollment and High Dropout Rates

Problem: Clinical trial fails to meet enrollment targets or experiences a higher-than-expected participant dropout rate.

Investigation & Solutions:

Analyze Consent Form Readability vs. Dropout:
- Symptom: The consent form's readability is significantly above the average adult reading level (8th grade).
- Tool: Quantitative analysis correlating Flesch-Kincaid Grade Level with trial dropout rates [19].
- Fix: Simplify the consent form. A large-scale study found that each additional grade level increase in a consent form's readability was associated with a 16% higher dropout rate (IRR: 1.16) [19]. Using a pre-validated, plain language template can shift the mean readability from the 10th grade to the 7th grade, directly addressing this barrier [15].
Review Document Length and Organization:
- Symptom: Consent forms are 15-20 pages long, acting as a deterrent to reading.
- Tool: Peer review, including by lay persons, to identify essential information [11].
- Fix: Develop a shortened consent form that covers crucial points a "reasonable person" would want, referring readers to appendices for further detail. This reduces the initial burden and facilitates comprehension of key information [11].

Frequently Asked Questions (FAQs)

Q1: What is the target readability grade level for an informed consent form, and why?

A: The target is the 8th-grade level or lower [5] [15]. This is because the average reading level of U.S. adults is at or below the 8th grade, and nearly half of all adults read at or below the 8th-grade level [19] [3]. Using a higher reading level excludes a significant portion of the population from truly understanding the research they are joining.

Q2: We are required to include complex scientific and legal concepts. How can we make these understandable?

A: You can maintain accuracy while improving clarity. Use plain language to translate complex concepts into simple ones without relying on parenthetical definitions [5]. Formatting is also crucial: use outlining, bullet points, large typeface, and diagrams to help readers follow complex ideas [11]. For legal and medical content, emerging research shows that Large Language Models (LLMs) with expert oversight can effectively simplify text while preserving essential medicolegal meaning [19].

Q3: What is the evidence that improving readability actually improves research outcomes?

A: Evidence is strong and growing. Improved readability is directly linked to:

Improved comprehension: Participants tested on a simplified consent form showed significantly better comprehension scores compared to the original form [3].
Reduced dropout rates: A study of 798 federally funded trials found a direct statistical association between higher readability scores and increased participant dropout [19].
Promotion of health equity: Populations that experience healthcare disparities are often over-represented among those with lower health literacy. Readable consent forms help ensure these groups can participate in and benefit from research [15] [3].

Q4: Our Institutional Review Board (IRB) is hesitant to approve simplified consent forms. How can we address this?

A: Reference the Federal Policy for the Protection of Human Subjects (the Common Rule), which requires that consent be "in language understandable to the subject" and "organized in a way that facilitates comprehension" [15]. Present evidence from peer-reviewed studies (like those cited here) that demonstrate simplified forms improve comprehension without compromising ethical or legal standards. Proposing a comprehension questionnaire can also reassure the IRB that understanding will be verified [11].

The table below summarizes key quantitative findings from recent research on informed consent form readability.

Table 1: Consequences of Poor Readability and Impact of Interventions

Metric	Baseline/Business-as-Usual	Post-Intervention	Source & Context
Average Readability (Grade Level)	10th grade [15]	7th grade (with template) [15]	Institutional review of 217 consents; post-intervention review of 82 consents.
Average Readability (Grade Level)	12.0 (±1.3) [19]	Not Applicable	Analysis of 798 federally funded clinical trial consents.
Readability in Gynecologic Cancer Trials	13th grade [7]	Not Applicable	Review of 103 informed consent forms at an NCI-designated institution.
Participant Dropout	Incidence Rate Ratio: 1.16	Not Applicable	Each 1-grade level increase in readability correlated with a 16% higher dropout rate across 798 trials [19].
Participant Comprehension	Baseline score (original form)	Significant improvement (Cohen's d=0.68)	Online survey of 192 adults; comprehension test performance was significantly better with a simplified form [3].
Template Adoption Rate	Not Applicable	49%	One year after introducing a plain language template, 49% of submitted consents used it [15].

Experimental Protocols

This protocol is based on a successful intervention that reduced mean consent form readability from the 10th to the 7th grade [15].

Objective: To systematically develop and implement a plain language informed consent template to improve readability and participant comprehension.

Materials:

Readability analysis software (e.g., Microsoft Word's built-in tool, Online-Utility.org, Readability Studio).
Plain language guidelines (see "Research Reagent Solutions").
Multi-stakeholder team (researchers, IRB members, health literacy experts, bioethicist).

Methodology:

Development: Draft a consent template that adheres to regulatory requirements and plain language principles.
Iteration: Refine the template through an iterative process with the stakeholder team. After each change, reassess readability to ensure it remains at or below the 8th-grade level.
User Testing: Conduct a focus group with individuals with low health literacy to gather qualitative feedback on understandability and layout.
Implementation: Make the final template available on the institution's IRB website. Promote it through internal communications and provide brief training sessions to IRB committees and investigators.
Evaluation: Conduct a retrospective analysis of submitted consent forms post-implementation to assess adoption rates and changes in average readability scores.

Protocol 2: Testing Comprehension Using a Simplified vs. Standard Form

This protocol is derived from a controlled study that demonstrated the superiority of a simplified form [3].

Objective: To quantitatively assess the impact of a simplified informed consent document on participant comprehension.

Materials:

Original informed consent document (ICD).
Simplified ICD version, created using plain language guidelines (targeting 8th-grade level).
Comprehension test (a series of true/false or multiple-choice questions based on the ICD content).
Individual differences measures (e.g., vocabulary test, working memory test).
Demographic survey.

Methodology:

Simplification: Select a standard ICD and create a simplified version by applying plain language guidelines (simpler words, shorter sentences, active voice, reduced passive voice).
Recruitment: Recruit a diverse sample of adult participants.
Testing: Randomly assign participants to read either the original or the simplified ICD. Subsequently, all participants complete the comprehension test.
Analysis: Perform a paired-samples t-test to compare comprehension test scores between the two groups. Use regression models to determine if the effect of simplification holds after accounting for demographic factors and individual differences (e.g., reading skill, working memory).

Logical Workflow Diagram

The diagram below visualizes the consequences of poor readability and the positive outcomes of implementing improvement strategies.

Research Reagent Solutions

Table 2: Essential Tools and Resources for Improving Consent Readability

Reagent / Tool	Function / Purpose	Example / Citation
Readability Calculators	Quantitatively assess the grade level required to understand a text passage.	Microsoft Word Readability Statistics, Automatic Readability Checker, Online-Utility.org [5] [19].
Plain Language Guidelines	Provide rules for simplifying text, including word choice, sentence structure, and organization.	U.S. Government Plain Language Guidelines, CDC's "Everyday Words for Public Health Communication" [5] [3].
Pre-Validated Consent Templates	Provide a starting point that is already optimized for readability and regulatory compliance.	Institution-specific templates (e.g., UAMS template that achieved 5th-grade readability) [15].
Color Contrast Checkers	Ensure text has sufficient contrast against its background for readers with low vision or color blindness.	WebAIM Contrast Checker, Acquia Color Contrast Checker [20] [21]. Compliance with WCAG AA (4.5:1 for normal text) is recommended [22] [23].
Large Language Models (LLMs)	Assist in the initial simplification of complex text, which is then refined and validated by human experts.	GPT-4 used to lower reading level while preserving medicolegal content [19].

Actionable Strategies for Writing Clear and Compliant Consent Forms

Solution: Create a shortened version that covers only crucial points.
Methodology: Use the "reasonable person standard" combined with the "subjective standard." Identify the information a reasonable person would need to make a decision, and be prepared to provide any specific information an individual participant requests [11].
Testing Protocol: Peer review the form with laypersons (non-healthcare professionals) to assess comprehensibility, especially for translated documents [11].

Solution: Set clear expectations at the start of the interview or writing process.
Methodology: Clearly state that you are writing for a non-specialist audience. For interviews, frame your request as an invitation to speak casually rather than a criticism of their language [24].
Testing Protocol: Read your text aloud. If you struggle to get through sentences, they are likely too complex for the average reader [25].

Problem: I need to use a precise technical term, but it may not be widely understood.

Solution: Define the term clearly upon its first use and provide a simpler alternative for the rest of the document.
Methodology: Use the "henceforth" technique. After using the full technical term once, state that you will refer to it with a simpler name for the remainder of the text [26].
Testing Protocol: Ask a colleague from a different field to review your work. If they cannot easily explain your key points, further revision is needed [25].

Frequently Asked Questions (FAQs)

What is the difference between necessary technical terminology and bad jargon?

Technical terminology becomes "jargon" when it unnecessarily narrows your audience or slows down reading, even for familiar readers [26]. Good technical terms are used for precision where needed; bad jargon is used when simpler alternatives exist.

Is it acceptable to use some jargon in scientific writing?

Yes, but only when the terms are absolutely necessary for accuracy. All essential jargon must be clearly defined. A common mistake is alternating between synonyms for the same term, which can confuse readers. Consistency is key [25].

Won't simplifying my language make my work seem less academic?

No. Simplified writing increases clarity and impact, which journals and readers value. The goal is not to "dumb down" your work, but to make it easier for readers to engage with your core ideas [25].

What are some practical alternatives to common complex words?

The table below provides clear alternatives.

Complex Term or Phrase	Plain Language Alternative
Utilize	Use [25]
Ameliorate	Improve [25]
Demonstrate efficacy	Works effectively [25]
The methodology employed facilitated the acquisition of data	The method allowed us to collect data [25]

Most Ethics Committees recommend a readability score of Grade 8 [11]. However, readability formulas only measure one aspect. Always conduct usability testing with people from your target audience to ensure true comprehension [27].

Experimental Protocols for Readability Improvement

Plan: Draft your consent materials using the Plain Language Materials Development Checklist to ensure understandability, actionability, and cultural relevance [27].
Conduct: Share the drafted materials with representative users from your participant population [27].
Evaluate: Use structured tools like the Patient Education Materials Assessment Tool (PEMAT-P) to systematically evaluate the material's effectiveness [27].
Revise: Incorporate feedback from the usability testing to refine the documents.

Protocol 2: Testing Participant Comprehension

Administer a Questionnaire: After the consenting procedure, give participants a questionnaire designed to test their understanding of key concepts, such as the trial design, risks, and their right to withdraw [11].
Use Participant Restatement: Beyond signing the form, ask the participant to write the salient features (e.g., that they understand they may receive a placebo) in their own handwriting. This ensures key points are focused on and understood [11].

Visualizing the Plain Language Writing Workflow

The Scientist's Toolkit: Key Reagents for Readability

Tool Name	Function
Plain Language Materials Development Checklist	A systematic tool to review materials for understandability, actionability, and cultural relevance [27].
Readability Score Calculators	Software tools that provide a quick check of text difficulty based on factors like word and sentence length [27].
Patient Education Materials Assessment Tool (PEMAT-P)	A validated rubric for specifically evaluating the usability of patient-facing educational materials [27].
Health Education Materials Assessment Tool	A form from the National Library of Medicine to evaluate the use of plain language in health education [27].

For informed consent forms (ICFs), a common and widely recommended goal is a reading level of 8th grade or lower [5] [28] [8]. This is measured using readability formulas like Flesch-Kincaid and SMOG. In terms of specific scores, you should aim for a Flesch-Kincaid Grade Level of 8 and a Flesch Reading Ease score of 70 or greater [5] [29].

The table below summarizes the target scores and their interpretations.

Readability Metric	Target Score	Interpretation
Flesch-Kincaid Grade Level	8.0 or lower	Text is understandable by the average 13- to 14-year-old student [29].
Flesch Reading Ease	70 or higher	Text is considered "fairly easy to read" for the average adult [30] [5].
SMOG Grade Level	8.0 or lower	Text is understandable by someone with 8 years of schooling [28].

The push for simpler ICFs is rooted in ethics and regulatory standards.

Ethical Imperative: Informed consent is a cornerstone of ethical human subjects research. The Belmont Report and subsequent regulations require that information be presented in language that is understandable to the participant [8]. Complex forms filled with medical jargon threaten autonomous decision-making.
Health Literacy Statistics: Over 80 million adults in the U.S. have limited health literacy skills. Only about 12% of adults have proficient health literacy. Using complex language can therefore exclude a significant portion of the population from participating in and benefiting from research [8].
Regulatory and Organizational Accountability: Healthy People 2030 expanded the definition of health literacy to include organizational health literacy, which is "the degree to which organizations equitably enable individuals to find, understand, and use information and services" [8]. This places the responsibility on researchers and institutions to communicate clearly.

Research has demonstrated that using plain language templates can significantly improve ICF readability. One academic institution found that using such a template lowered the average readability of their consent forms from a "difficult" 11th-grade level to an "average" 8th-grade level [8].

How do I measure the readability of my documents?

You can measure readability using software tools that apply the standard formulas.

Flesch-Kincaid Formula

This is the most widely used test and is integrated into many word processors. It calculates a U.S. grade level based on average sentence length and average syllables per word [30] [31].

Formula: 0.39 * (Total Words / Total Sentences) + 11.8 * (Total Syllables / Total Words) - 15.59

SMOG (Simplified Measure of Gobbledygook) Formula

The SMOG formula is a reliable method that estimates the years of education needed to understand a text. It is based on the number of polysyllabic words (words with three or more syllables) [28].

Simplified Formula for a 30-sentence sample: SMOG Grade = Square root of (Number of polysyllabic words) + 3

Step-by-Step Measurement Protocol

Experiment Protocol: Measuring Readability with SMOG

This protocol is adapted from the Harvard T.H. Chan School of Public Health's Center for Health Communication [28].

Gather Sample Sentences:
- For a long document, select a passage of 30 sentences: 10 consecutive sentences from the beginning, 10 from the middle, and 10 from the end of the document.
- For documents shorter than 30 sentences, use the entire text and follow a specific calculation to extrapolate (see the full guide for details) [28].
Count Polysyllabic Words:
- In your 30-sentence sample, count every word that has three or more syllables.
- Tips for counting:
  - Hyphenated words count as a single word.
  - Include numbers and proper nouns, counting them as if they were written out.
  - Include abbreviations as if they were spelled out completely (e.g., "COVID" would be counted as three syllables) [28].
Apply the SMOG Formula:
- Take the square root of the number of polysyllabic words you counted.
- Add 3 to this square root.
- The result is the estimated reading grade level.
- Example: If you counted 26 polysyllabic words, the square root is ~5.1. SMOG Grade = 5.1 + 3 = 8.1 (8th grade level) [28].

The following workflow diagram illustrates the SMOG measurement process.

Most researchers use automated tools to perform these calculations instantly.

Microsoft Word: Enable readability statistics in the proofing options. After a spell check, it will display both Flesch-Kincaid scores.
Online Checkers: Use free websites like the Automatic Readability Checker or WebAIM Contrast Checker (which also checks color accessibility) [5] [17].
Dedicated Software: Tools like Readable and Seven Formulas software provide scores from multiple readability formulas [29] [8].

Improving readability is an active process of writing and editing. Here are key strategies based on regulatory guidance and plain language principles [5]:

Use Plain Language: Replace complex medical or scientific jargon with simple, common words. For example, use "about" instead of "approximately" and "high blood pressure" instead of "hypertension" [5].
Write Short, Simple Sentences: Break long, complex sentences into multiple shorter ones, aiming for one main thought per sentence [5].
Use Active Voice: Write "We will measure your blood pressure," instead of the passive "Your blood pressure will be measured by us" [5].
Leverage Formatting:
- Use a size 12 Sans-serif font (e.g., Arial, Calibri).
- Ensure left-justified, right-ragged text and ample white space.
- Use bulleted or numbered lists for three or more items.
- Use bold or italics sparingly to emphasize critical points, but avoid using all caps [5].
Ensure Color Contrast (for digital forms): If your consent form is digital or contains graphics, ensure sufficient color contrast. The Web Content Accessibility Guidelines (WCAG) require a minimum contrast ratio of 4.5:1 for normal text against its background to aid users with visual impairments [17].
Conduct a Layperson Review: Have someone unfamiliar with your research (a "layperson") read the form and ask them comprehension questions. This is the most effective way to test true understanding [5].

Research Reagent Solutions for Readability Improvement

The following table lists essential "tools" for designing and executing a successful consent form readability project.

Research Reagent	Function in Readability Experiment
Plain Language ICF Template	A pre-formatted document with simplified language and structure that serves as a starting point, ensuring consistency and adherence to best practices [8].
Automated Readability Software	Tools (e.g., Readable, Seven Formulas) used to quantitatively assess and score the reading grade level of a text draft [8].
Style Guide (e.g., CDC's "Everyday Words")	A reference document that provides plain language alternatives for complex public health and scientific terms, ensuring consistent word choice [5].
Color Contrast Analyzer	A digital tool (e.g., WebAIM's Contrast Checker) that verifies the visual accessibility of text and background colors on digital forms against WCAG standards [17].
Lay Reviewer Questionnaire	A set of questions designed to test a potential subject's comprehension of the key elements of the study after reading the consent form [5].

Frequently Asked Questions (FAQs)

Our IRB requires precise legal and medical terminology. How can we simplify the form without losing necessary meaning?

You can include precise terminology while ensuring understanding by using plain language explanations. Instead of putting the definition in parentheses next to the complex term, rewrite the entire sentence or paragraph using simple language. You can also include a separate glossary for reference [5].

While the FDA does not specify a numeric grade level, its regulations state that information presented to subjects must be "in language understandable to the subject" [32] [8]. The FDA also requires that advertising for research subjects, which is considered the start of the informed consent process, must be reviewed by an IRB to ensure it is not coercive and makes no claims beyond what is in the approved protocol and consent document [32]. Achieving an 8th-grade reading level is the operational standard used by the research community to meet this regulatory requirement.

Yes, the "Key Information" section is particularly critical. The revised Common Rule mandates this section, which should be a concise and easily understandable summary presenting the most important information about the study (e.g., its voluntary nature, main procedures, and key reasons for/against joining) [8]. Ensuring this section has a very low reading level is essential for facilitating a potential subject's initial decision-making.

Within the broader research on strategies to improve informed consent form (ICF) readability, formatting is not merely a cosmetic concern. It is a critical factor that directly influences a potential participant's ability to understand, process, and recall complex study information. Effective use of headings, bullets, and visual aids can significantly reduce cognitive load, guide the reader through the information logically, and support the principle of respect for persons by facilitating truly informed decision-making. This guide provides evidence-based, practical solutions for researchers aiming to enhance the clarity and participant comprehension of their consent documents.

Troubleshooting Guides and FAQs

Answer: You can use built-in software tools to get a quantitative readability score. The goal for ICFs is a reading level at or below the 8th grade [5].

Method: Use the Flesch-Kincaid readability test in Microsoft Word.
Steps:
- Tap File > Options > Proofing.
- Check the box for "Show readability statistics."
- Run a spell check. A window will pop up displaying the Flesch-Kincaid Grade Level [5].
Target Score: Aim for a score of 70 or greater on the Flesch Reading Ease test, which corresponds to an 8th-grade reading level or lower [5] [6].

Answer: Implement clear structural and visual cues to enhance scannability and reduce reader fatigue.

Use Headings: Create a clear hierarchy of information with bolded headings [5].
Incorporate White Space: Use margins of at least 1 inch and avoid "squeezing" content to minimize page count [5].
Implement Lists: Use bulleted or numbered lists for any series of three or more items, such as study procedures or risks [5].
Apply Text Emphasis Judiciously: Use bold or italics to highlight critical points, but avoid overusing them or USING ALL CAPS, which is difficult to read [5].

Answer: Commit to using plain language principles.

Replace Jargon: Use simple, common words instead of scientific or legal jargon. Do not use the word and then the definition in parentheses; just use the plain language term from the start [5].
Use Short Words: Prefer words with fewer than three syllables (e.g., "use" instead of "utilize," "about" instead of "approximately") [5].
Write Short Sentences: Break long, complex sentences into one thought per sentence [5].
Use Active Voice: Write "We will measure your blood pressure," instead of the passive voice, "Your blood pressure will be measured by us." [5]

Answer: Yes, several resources and tools are available to assist researchers.

The Key Information (RUAKI) Checklist: A 16-item tool with demonstrated validity and reliability to help apply plain language principles to the key information section of consent forms [33].
Informed Consent Form Navigator: A web-based tool that guides researchers through creating a study-specific ICF, ensuring regulatory compliance and readability [34].
Consent Builder: An innovative tool that uses REDCap and LaTeX to generate consistently formatted consent documents for multicenter trials, combining standardized study descriptions with local site verbiage [35].
Plain Language Templates: Academic institutions often provide templates. One study showed that using a plain language template improved ICF readability from a "difficult" grade 11 level to an "average" grade 8 level [8].

How can I validate that my formatting changes actually improve understanding?

Answer: Combine quantitative readability scores with human-centered evaluation techniques.

Conduct a "Teach-Back": Ask a layperson to read your document and then explain the study back to you in their own words. This helps identify explanations that are commonly misunderstood [34].
Usability Testing: Engage end-users (e.g., potential participants or research staff) in testing the form. Use scenarios that reflect real-life interactions to identify points of confusion and areas for enhancement [36].

Experimental Protocols and Data

► Protocol 1: Longitudinal Readability Assessment

This protocol outlines the methodology used to evaluate longitudinal changes in ICF readability at an academic institution following the introduction of a plain language template [8].

Objective: To determine the impact of a plain language ICF template on the readability of institutional consent forms over time.
Methodology:
- Sampling: ICFs from investigator-initiated studies were collected across three time periods: before a template was introduced (P1), after the original template (P2), and after a revised template (P3) [8].
- Readability Analysis: For each ICF, 600-word samples were taken from the beginning, middle, and end. Samples were cleaned (e.g., bullet points removed) [8].
- Software: Cleaned samples were analyzed using Seven Formulas software to generate scores from three validated formulas: Flesch-Kincaid, SMOG, and Fry Graph. Scores were averaged for a mean grade level [8].
- Statistical Analysis: Mean readability scores across time periods were compared using one-way analysis of variance (ANOVA) in SPSS [8].
Key Quantitative Data:

Table 1: Institutional Mean Readability Scores Over Time [8]

Time Period	Description	Number of ICFs	Mean Grade Level	Readability Category
P1	No template available	84	11.10	Difficult
P2	After original template	82	10.03	Difficult
P3	After updated template	57	9.22	Average

Table 2: Readability Based on Template Use [8]

Template Used	Description	Number of ICFs	Mean Readability
NT	No template used	139	11.33
T1	Original template used	43	8.28
T2	Updated template used	41	8.54

► Protocol 2: Cross-Sectional Readability Evaluation

This protocol describes a method for assessing the current state of ICF readability across a large sample of forms, as used in a Tanzanian study [6].

Objective: To assess the readability of a contemporary sample of health research ICFs approved by a national ethics committee.
Methodology:
- Study Design: Retrospective cross-sectional study [6].
- Sample Size: 266 English-version health RICFs from 2020-2021, selected via stratified and systematic random sampling [6].
- Data Collection: PDF forms were converted to Word format. The Flesch Reading Ease (FRE) and Flesch-Kincaid Readability Grade Level (FKRGL) formulas in Microsoft Word were used to determine scores, page counts, and sentence lengths [6].
- Data Analysis: Data were analyzed with IBM SPSS Statistics. Readability scores were categorized, and Pearson’s correlation was used to assess the relationship between sentence length and reading difficulty [6].
Key Quantitative Data:

Table 3: Readability Results from Cross-Sectional Assessment [6]

Metric	Finding	Percentage
Page Count	Had recommended page numbers (1-3 pages)	65.4%
Sentence Length	Had longer sentences (>15 words per sentence)	81.6%
Readability	Were difficult to read (requiring > US grade 8)	80.5%

Visual Workflows and Aids

► ICF Readability Assessment Workflow

This diagram illustrates the step-by-step process for systematically assessing the readability of an Informed Consent Form, as derived from experimental protocols.

This diagram visualizes the innovative two-part consent model for multicenter trials, which separates study science from local site language to improve consistency and clarity [35].

Table 4: Key Research Reagent Solutions for Readability Improvement

Tool Name	Type	Primary Function
Flesch-Kincaid Scale [34] [5]	Readability Formula	Quantifies the U.S. grade level needed to understand a text.
Key Information (RUAKI) Checklist [33]	Evaluation Tool	A validated 16-item checklist to assess the clarity of the key information section.
Plain Language ICF Template [8]	Document Template	A pre-formatted template using plain language principles to lower reading grade level.
Teach-Back Method [34]	Communication & Validation	Confirms patient understanding by having them explain information in their own words.
Consent Builder Tool [35]	Software Platform	A web-based tool to generate consistent, well-formatted consent documents for multicenter trials.
Automatic Readability Checker [5]	Online Tool	Free websites that provide instant readability scores for pasted text.

Obtaining informed consent is a fundamental ethical practice in human subjects research. The informed consent form (ICF) is intended to support autonomous decision-making, but this goal is threatened if the materials are difficult to read [8]. With over 80 million adults in the US having limited health literacy skills, optimizing subjects' ability to read and understand ICFs is crucial for ethical research conduct and equitable participation [8]. This technical guide provides evidence-based strategies for structuring risk, benefit, and procedure explanations to enhance comprehension within research settings.

Quantitative Assessment of Readability Improvements

Longitudinal Readability Outcomes

The implementation of plain language templates at an academic medical center demonstrated significant improvements in ICF readability across multiple assessment periods [8].

Table 1: Institutional Readability Score Improvements Over Time

Time Period	Period Description	Number of ICFs Assessed	Mean Grade Level	Readability Category	Percentage of ICFs Rated "Difficult"
P1 (2013-2015)	No plain language template available	84	11.10	Difficult	82.1%
P2 (2016-2017)	After original template introduction	82	10.03	Difficult	46.3%
P3 (2019-2020)	After updated template introduction	57	9.22	Average	21.1%

Template-Driven Readability Enhancement

The use of structured templates specifically designed for plain language communication resulted in substantial readability improvements regardless of the template version used [8].

Table 2: Readability Outcomes by Template Utilization

Template Used	Template Description	Number of ICFs Assessed	Mean Readability (Grade Level)	Readability Category	Statistical Significance (vs. No Template)
NT	No plain language template used	139	11.33	Difficult	Not applicable
T1	Original plain language template	43	8.28	Average	p < 0.0001
T2	Updated plain language template (Revised Common Rule)	41	8.54	Average	p < 0.0001

Experimental Protocols for Readability Assessment

Standardized Readability Evaluation Methodology

Researchers can employ this validated protocol to assess consent form readability:

Sample Selection: Extract 600-word samples from the beginning, middle, and end of each ICF text to ensure representative sampling [8].
Text Cleaning Protocol:
- Remove bullet points and extraneous punctuation
- Clean honorifics (e.g., remove period from "Dr. Smith" to avoid software misinterpretation as sentence end)
- Standardize formatting across samples [8]
Readability Analysis:
- Process cleaned samples through validated readability software (e.g., Seven Formulas)
- Generate scores from multiple validated formulas: Flesch-Kincaid, SMOG, and Fry Graph [8]
- Calculate mean readability score from all three formulas
- Categorize scores into difficulty levels: "easy," "average," or "difficult" [8]
Statistical Comparison:
- Use one-way analysis of variance (ANOVA) for group comparisons
- Employ statistical software (e.g., IBM SPSS) for analysis [8]

Readability Improvement Workflow

The following diagram illustrates the systematic workflow for developing and testing readable consent forms:

Adapted from customer service troubleshooting methodologies, this structured approach helps researchers address common consent understanding issues [37] [38]:

Q: How can I reduce the reading level of complex medical terminology in consent forms? A: Replace medical and scientific jargon with simple, plain language words without including both the term and definition in parentheses. Just use the plain language equivalent [5].

Q: What sentence structure improvements enhance comprehension? A: Break sentences with multiple thoughts into one thought per sentence. Use active voice where the subject does the action (e.g., "We will measure your blood pressure") rather than passive voice (e.g., "Your blood pressure will be measured") [5].

Q: What visual formatting practices improve readability? A: Use size 12 sans serif fonts (Arial, Calibri, Tahoma), maintain minimum 1-inch margins, use left-justified/right-ragged format, and employ bulleted or numbered lists when three or more items are included in the text [5].

Q: How can I validate that consent forms are truly understandable to participants? A: Have a lay person read your document and ask them comprehension questions to identify areas needing clarification [5].

Accessibility-Compliant Color Contrast Requirements

Enhanced contrast requirements ensure text is readable by participants with visual impairments [39] [40]:

Standard text: Minimum contrast ratio of 7.0:1 between text and background colors [39] [40]
Large-scale text (18pt or 14pt bold): Minimum contrast ratio of 4.5:1 [39] [40]
Exception: Text that is purely decorative or doesn't convey meaningful content [39]

Color Application Framework for Visual Hierarchy

Based on data visualization principles, apply these color guidelines to consent materials [41]:

Qualitative Palettes: Use distinct hues for categorical information when variable is categorical without inherent ordering [41]
Sequential Palettes: Use lightness progression for numeric or ordered values, with lighter colors typically indicating lower values [41]
Diverging Palettes: Combine two sequential palettes with shared endpoint for variables with meaningful central value [41]

Table 3: Color Application Guidelines for Consent Documents

Palette Type	Appropriate Use Cases	Implementation Guidelines	Accessibility Considerations
Qualitative	Different consent sections, risk categories	Use distinct hues, limit to ≤10 colors, avoid similar lightness/saturation	Ensure sufficient contrast between all colors and background
Sequential	Risk severity levels, probability scales	Vary lightness progressively, consider warm-to-cool hue transition	Maintain minimum 4.5:1 contrast for all text elements
Diverging	Benefit-risk comparisons, preference scales	Use distinctive hues for each side of center, light colors for central values	Test with color blindness simulators for red-green/blue-yellow confusion

Table 4: Research Reagent Solutions for Consent Readability Optimization

Tool/Resource	Function	Application Context
Plain Language ICF Template	Structured framework for consent drafting	Standardizes readability elements across study documents [8]
Readability Assessment Software (Seven Formulas)	Calculates multiple validated readability scores	Objective evaluation of consent form reading level [8]
Color Contrast Analyzers	Verify compliance with accessibility standards	Ensure visual accessibility for participants with visual impairments [39] [40]
Health Literacy Resources	Guidelines for appropriate reading level	Adaptation of content for diverse literacy levels [8]
Flesch-Kincaid Readability Statistics	Integrated readability checking in word processors	Accessibility evaluation during document development [5]
Lay Reviewer Protocol	Structured comprehension assessment by non-experts	Identifies problematic terminology and complex concepts [5]

Risk Communication Framework

Risk Prioritization and Explanation Methodology

Effective risk communication in consent forms requires careful prioritization and clear explanation. Adapt these risk management principles for participant communication [42] [43]:

Risk Identification: Systematically identify potential risks participants might encounter, considering both likelihood and impact [42]
Risk Analysis: Assess risks by evaluating both likelihood of occurrence and potential impact on participants using consistent scales [42]
Risk Prioritization: Present risks in order of importance based on severity and probability, ensuring participants understand which risks require most consideration [43]

Risk Communication Protocol

The following diagram illustrates the process for developing effective risk explanations in consent forms:

Informed consent forms (ICFs) are fundamental to ethical research, yet they often present significant comprehension barriers for potential participants. Despite recommendations from major institutions like the National Institutes of Health that health materials be written at a 7th to 8th grade level, most ICFs are written above the 10th grade level, making them too difficult for nearly half of U.S. adults [3]. This technical support center provides researchers with evidence-based tools and methodologies to systematically improve ICF readability, thereby promoting greater participant comprehension and advancing health equity in research enrollment.

Frequently Asked Questions (FAQs)

Q1: What is the recommended reading grade level for informed consent forms? Most institutions, including Johns Hopkins Medicine and the University of Michigan, recommend that consent forms should be written at no higher than an 8th grade reading level. This aligns with data showing the average reading level of U.S. adults is at or below 8th grade [15] [2] [44].

Q2: Which readability formulas are most appropriate for assessing consent forms? Multiple formulas are commonly used, with Flesch-Kincaid being among the most prevalent. The table below summarizes key readability indices and their interpretation [5] [1]:

Table 1: Readability Indices for Informed Consent Forms

Index Name	Score Interpretation	Target Range for ICFs
Flesch Reading Ease	0 (Very Difficult) to 100 (Very Easy)	60-100 (Standard to Very Easy) [5]
Flesch-Kincaid Grade Level	U.S. school grade level (0-18)	≤ 8th grade [15] [2]
SMOG Index	U.S. school grade level (0-18)	≤ 8th grade [1]
Gunning Fog Index	U.S. school grade level (0-20)	≤ 8th grade [1]

Q3: What are the most effective plain language strategies for improving readability? Key strategies include using simple words with fewer than three syllables, writing short sentences with one thought each, employing active voice, and using second-person ("you") to address the participant directly [5] [2]. Formatting choices like 12-point sans-serif font, left-justified text, and adequate white space also significantly enhance readability [5].

Q4: How can I check the readability score of my consent form? Many word processors, including Microsoft Word, have built-in readability checkers. To enable it in Word: go to File > Options > Proofing and check "Show readability statistics." After running a spell check, it will display the Flesch-Kincaid Grade Level [5] [2].

Q5: Are electronic consent (eConsent) tools effective for improving understanding? Yes. eConsent platforms can enhance comprehension by incorporating multimedia elements, interactive assessments, and tailored content for different learning styles and literacy levels. They also provide robust audit trails for compliance [45].

Troubleshooting Common Readability Issues

Problem: Consent form readability scores remain too high after initial revisions.

Solution: Implement a systematic, multi-step protocol. A study at the University of Arkansas for Medical Sciences (UAMS) demonstrated success by first analyzing baseline readability, then developing and providing a plain-language template, followed by training for investigators. This intervention reduced mean readability from 10th grade to 7th grade [15]. Have a layperson or a community review board read the document and provide feedback on comprehension [5] [46].

Problem: Ensuring regulatory compliance while using simplified language.

Solution: Utilize institutional templates that are pre-approved by your IRB. These templates are designed to include all required regulatory elements in plain language. The University of Michigan and UAMS offer such templates, which include the key information elements mandated by the Revised Common Rule [44] [46].

Problem: Participants struggle with understanding complex clinical trial concepts.

Solution: Replace jargon with clear explanations. For example, instead of "randomized," use "like the flip of a coin." Define necessary terms like "placebo" when first introduced: "A placebo is an inactive substance that looks like the study drug, but contains no medication" [2]. eConsent tools can further explain these concepts through embedded videos or interactive graphics [45].

Experimental Protocols for Readability Improvement

Protocol 1: Implementing and Validating a Plain Language Template

This protocol is based on a successful intervention at UAMS that significantly improved ICF readability [15].

Objective: To assess the readability of Institutional Review Board (IRB)-approved ICFs, implement a plain language template, and measure the impact of the intervention.

Methodology:

Baseline Assessment: Conduct a retrospective analysis of recently approved ICFs. Use a minimum of three readability formulas (e.g., Fry Graph, Flesch-Kincaid, SMOG) on a sample of forms to establish a mean baseline readability score.
Template Development: Collaborate with health literacy experts, the IRB, and community stakeholders to develop a plain-language ICF template. The template should incorporate:
- Pre-written, IRB-approved text for standard sections.
- Instructions and examples for study-specific content.
- Real-time readability score feedback.
Intervention: Make the template available to researchers via the IRB website. Provide complementary training sessions on its use and the principles of plain language.
Post-Intervention Assessment: After a set period (e.g., one year), prospectively analyze a new sample of ICFs using the same readability formulas. Compare the mean readability and the percentage of forms at or below the 8th-grade level against the baseline.

Expected Outcomes: The UAMS study resulted in a 49% adoption rate of the template, which shifted the mean readability of ICFs from the 10th grade to the 7th grade and led to a 658% increase in forms written at or below the 8th-grade level [15].

This protocol details a controlled study to measure the comprehension impact of a simplified ICF [3].

Objective: To assess the difference in participant comprehension between an original clinical trial ICF and a simplified version.

Methodology:

Document Preparation: Select a standard ICF from a clinical trial (e.g., for colorectal cancer). Create a simplified version by applying plain language guidelines, focusing on simpler word choice (semantics) and sentence structure (syntax).
Readability Analysis: Submit both versions to readability analysis (e.g., Flesch-Kincaid Grade Level) and writing analysis tools to quantify reductions in long sentences and passive voice.
Participant Recruitment: Recruit a diverse sample of adults. Collect demographics and administer tests for reading skill and working memory.
Testing: Randomly assign participants to read either the original or simplified ICF. Following the reading, administer a comprehension test with true/false questions based on the document's content.
Data Analysis: Use statistical tests (e.g., paired-samples t-test, regression models) to compare comprehension scores between the two groups and to determine if demographics or cognitive skills moderate the effect.

Expected Outcomes: The referenced pilot study found that the simplified ICF (FKGL 8.2) led to a statistically significant improvement in comprehension test performance compared to the original (FKGL 12.3). This effect held true regardless of participants' age, race, reading skill, or working memory [3].

The Researcher's Toolkit: Software and Template Solutions

The following table outlines key digital tools and resources that facilitate the creation of readable, compliant consent forms.

Table 2: Research Reagent Solutions for Informed Consent

Tool Name	Type	Primary Function	Key Features
Informed Consent Navigator [46]	Web-based Tool	Guides researchers in creating plain-language ICFs.	Provides IRB-approved text snippets, offers real-time readability feedback, ensures adherence to an 8th-grade reading level.
Microsoft Word Readability Checker [5]	Built-in Software Feature	Calculates readability statistics within a word processor.	Provides Flesch-Kincaid Grade Level and Flesch Reading Ease scores after a grammar check.
Medrio [47]	Electronic Consent (eConsent) Software	Facilitates digital consent for clinical trials.	Cloud-based, enhances trial efficiency and data integrity, supports multimedia integration.
DocResponse [47]	Electronic Consent (eConsent) Software	Provides a comprehensive digital patient check-in platform.	Includes customizable eConsent forms, telehealth integration, and HIPAA-compliant data security.
IRB-HSBS Informed Consent Template [44]	Institutional Template	Pre-formatted document for drafting ICFs.	Includes all required Common Rule elements, uses recommended plain language, and is pre-reviewed for regulatory compliance.

The diagram below visualizes a systematic workflow for developing an effective, readable informed consent form, integrating institutional templates and readability software.

Overcoming Common Hurdles and Optimizing the Consent Process

Frequently Asked Questions

1. What is the simplest way to explain randomization to a potential participant? Randomization is like flipping a coin to decide which treatment a participant receives. In clinical trials, a computer uses a similar random process to assign participants to different groups. This is a fair way to ensure that the groups are as similar as possible, so that any differences in outcomes at the end of the study can more confidently be attributed to the treatments being tested, rather than to other factors [48] [49].

2. Why is it important for a placebo to look identical to the active treatment? A placebo must be indistinguishable from the active treatment to maintain "blinding." This means that the participant (and often the doctor) does not know which treatment is being administered. If they could tell the difference, their expectations about the treatment could unconsciously influence how they feel or report their symptoms, which would make the trial results less reliable [50].

3. We are testing a medical device, not a pill. How can we design a credible placebo? Designing a placebo for a device, like a hand splint, requires careful consideration. It is crucial to identify the "active" mechanism of the device and create a placebo that lacks this key ingredient but is otherwise identical in appearance and feel. In one project, researchers directly involved service users (patients) to help design a placebo splint. The users identified which features provided therapeutic support and helped create a placebo that was credible and acceptable for a clinical trial [51].

4. How can the readability of our consent form affect our clinical trial? Research shows that difficult-to-read consent forms can hinder participant comprehension and are statistically associated with higher dropout rates [6] [19]. One study of 798 trials found that each increase in the Flesch-Kincaid Grade Level of a consent form was associated with a 16% higher dropout rate [19]. Ethics guidelines often recommend that forms should be written at an 8th-grade reading level or lower to ensure good understanding [6].

5. What are the main methods of randomization, and how do I choose? The choice of randomization method depends on the need for balance in group sizes and participant characteristics. The table below summarizes common methods.

Randomization Method	Brief Description	Key Advantage	Key Consideration
Simple Randomization	Like flipping a coin for each assignment [48].	Maximizes randomness and minimizes predictability [48].	In small trials, can lead to significant imbalances in the number of subjects in each group [48].
Block Randomization	Assignments are made in small, balanced blocks (e.g., of 4 or 6) [48].	Keeps the number of subjects in each group closely balanced throughout the trial [48].	If the block size is known, the last assignment(s) in a block can be predicted, which may introduce bias [48].
Stratified Randomization	Randomization is performed separately within specific subgroups (e.g., by study site or disease severity) [48].	Ensures a balance of key prognostic factors (like age or gender) across the treatment groups [48].	Using too many stratification factors can lead to a complex design with very few subjects in some strata [48].

6. What is the "placebo effect" and what does it actually control for in a trial? The term "placebo effect" often refers to a combination of several factors that can make a participant feel better, regardless of the specific treatment. These include [50]:

Natural history: Some people get better over time on their own.
The Hawthorne effect: People may change their behavior because they know they are being studied.
Expectation effects: A participant's belief that a treatment will work can influence their outcome. A well-designed placebo control helps to measure this collective "noise," allowing researchers to isolate the true biological effect of the active treatment component [50] [52].

Data and Readability

The tables below present key quantitative data on consent form readability and its impact, providing a evidence-based rationale for simplification.

Table 1: Readability Analysis of Health Research Informed Consent Forms (RICFs)

Metric	Findings from a Retrospective Study of 266 RICFs	Recommended Benchmark
Readability	80.5% were difficult to read, requiring a US grade 10 level for comprehension [6].	Grade 8 level or below [6] [19].
Sentence Length	81.6% contained longer sentences [6].	Less than 15 words per sentence [6].
Page Length	65.4% adhered to the recommended page number length [6].	Less than or equal to 3 pages [6].

Table 2: Association Between Consent Form Readability and Trial Dropout Rates

Readability Metric	Association with Dropout Rate	Statistical Significance
Flesch-Kincaid Grade Level	Each 1-grade level increase was associated with a 16% higher dropout rate (Incidence Rate Ratio: 1.16) [19].	P < 0.001 [19]

Experimental Protocols

Protocol 1: Implementing Block Randomization This methodology ensures treatment groups remain balanced in size throughout the enrollment period [48].

Define the block size: Choose a small, even number that is a multiple of the number of treatment groups (e.g., block size of 4 for a 2-group trial).
Create allocation sequences: For each block, create all possible sequences that contain an equal number of assignments for each treatment. For a block of 4 and two treatments (A and B), possible sequences are AABB, ABAB, ABBA, BAAB, BABA, BBAA.
Randomize the sequence of blocks: Randomly select one of these sequences for the first block of participants, then randomly select another for the next block, and so on.
Conceal the sequence: The allocation sequence should be generated by a central system and concealed from the investigators enrolling participants to prevent selection bias.

Protocol 2: Designing a Placebo for a Digital Health Application This protocol ensures the placebo control for a digital intervention is credible [50].

Hypothesize the active ingredient: Clearly define the specific component of the app you believe is therapeutically effective (e.g., the cognitive behavioral therapy algorithm).
Create a structurally equivalent sham: Develop a control app that is identical to the active app in its non-specific features. This includes:
- Number and duration of sessions.
- User interface and visual design.
- Level of user interaction and engagement.
Remove the active component: The placebo app should lack the core therapeutic mechanism (e.g., it may provide general health information instead of a structured therapeutic program).
Test for blinding: After the trial, ask participants to guess which group they were in. Successful blinding is indicated if guesses are no better than chance.

Protocol 3: Simplifying Informed Consent Forms with AI and Expert Review This methodology uses large language models (LLMs) to improve readability while preserving content [19].

Extract key sections: Manually identify and extract the core sections of the consent form, such as Purpose, Benefits, Risks, Alternatives, Voluntariness, and Confidentiality.
AI-powered simplification: Input the text into an LLM (e.g., GPT-4) with a prompt such as: "While preserving content and meaning, convert this text to the average American reading level by using simpler words and limiting sentence length to 10 or fewer words." [19].
Measure readability change: Calculate the Flesch-Kincaid Grade Level of the text before and after simplification to quantify the improvement.
Expert medicolegal review: Have a healthcare lawyer and a panel of clinicians independently review the simplified text to confirm it retains medical and legal accuracy.

Workflow Diagrams

Randomization Implementation Workflow

Placebo Design and Validation Workflow

The Scientist's Toolkit

Tool or Resource	Function in Research
R Software	A powerful, open-source statistical computing environment that can be used to implement various randomization methods, from simple to adaptive [48].
Stratification Factors	Pre-specified baseline variables (e.g., study site, disease severity) used to create subgroups within which randomization is performed separately, ensuring these factors are balanced across treatment arms [48].
Flesch-Kincaid Tests	Readability formulas built into many word processors that calculate the U.S. grade level needed to understand a text, allowing researchers to quantitatively assess their consent forms [6] [19].
Large Language Models (LLMs)	AI tools, such as GPT-4, that can be prompted to simplify complex text while preserving meaning, offering a potential method for improving consent form readability [19].
Participatory Design Fora	Structured sessions where service users (patients) are actively involved in the design of interventions and placebos, leveraging their expertise to ensure credibility and acceptability [51].

FAQs on Medical Terminology and Readability

Why is managing complex terminology so important in informed consent forms (ICFs)?

The primary goal of an informed consent form is to ensure the participant's comprehension. Using complex medical terminology without explanation can create significant barriers to understanding. Research indicates that over 80% of health research ICFs were difficult to read, often requiring a US grade 10 education level or higher to understand the presented information [6]. Another systematic review found that 76.3% of analyzed ICFs had poor readability [53]. Poor comprehension can prevent participants from making truly autonomous decisions about their participation.

How can I assess if my ICF is written at an appropriate level?

You can use established readability formulas to quantitatively assess your document. Regulatory agencies in the U.S. generally recommend that ICFs be written at a sixth to eighth-grade reading level [14]. The most commonly used tools include [53] [14]:

Flesch Reading Ease (FRE): Scores from 0 (very difficult) to 100 (very easy). A score above 60 is generally considered easily readable for most of the population [6] [53].
Flesch-Kincaid Grade Level: Outputs a U.S. grade level. The target is typically ≤ 8th grade [14]. These formulas are often built into common software like Microsoft Word, which can automatically calculate scores after a spelling and grammar check [6].

What are the best strategies for including unavoidable technical terms?

When a complex term is necessary, it should be actively defined and explained, not just included. Effective strategies include:

Providing a Glossary: Create a simple glossary for complex terms at the end of the document.
Using Analogies: Explain complex processes using familiar, everyday concepts.
In-Text Definitions: Place a brief, plain-language explanation in parentheses immediately after the technical term's first use.
Supplemental Visual Aids: Use diagrams or illustrations to clarify anatomical or procedural information [54].

Are there regulatory constraints on simplifying language?

Yes. While simplifying language is encouraged, the information must remain accurate and complete. The consent form must not include any exculpatory language, which is text that waives or appears to waive a participant's legal rights or releases the investigator, sponsor, or institution from liability for negligence [14]. Always check with your Institutional Review Board (IRB) for specific formatting and content requirements [14].

Troubleshooting Guide: Readability Challenges and Solutions

Problem	Symptom	Solution
High Reading Grade Level	Flesch-Kincaid score above grade 8 [14].	Break long sentences into shorter ones (aim for <15 words/sentence). Replace multi-syllable words with simpler synonyms where possible without losing meaning [6].
Low Readability Score	Flesch Reading Ease score below 60 [53].	Use the active voice. Reduce sentence length and word complexity. Test the revised form with a readability calculator [6].
Overuse of Technical Jargon	The form is filled with specialized terms unfamiliar to a layperson.	For each necessary technical term, provide a brief, clear definition upon its first use. Collect all defined terms in a simple glossary [14].
Participant Comprehension Failure	Participants are unable to correctly explain the study's purpose, procedures, risks, or benefits during questioning.	Supplement the written form with visual aids (diagrams, charts) and engage in a structured, interactive consent conversation to verify understanding [54].

Experimental Protocols for Assessing and Improving Readability

Protocol 1: Quantitative Readability Assessment

Objective: To objectively measure the reading difficulty of a draft Informed Consent Form using standardized formulas.

Materials:

Draft Informed Consent Form (in electronic format, e.g., Microsoft Word)
Computer with readability software (e.g., Microsoft Word's built-in tool)

Methodology:

Document Preparation: Open the ICF document in Microsoft Word. Remove all identifying information (e.g., researcher names, institution logos) to de-identify the text for analysis [6].
Enable Readability Statistics:
- Navigate to: File > Options > Proofing.
- Under "When correcting spelling and grammar in Word," check the box for "Show readability statistics." [6]
Run Assessment:
- Complete a full spelling and grammar check on the document (Review > Spelling & Grammar).
- Once the check is complete, the Readability Statistics window will automatically appear.
Data Recording:
- Record the Flesch Reading Ease score and the Flesch-Kincaid Grade Level [6].
- Also note the average sentences per paragraph and words per sentence.

Interpretation of Results:

Target: Flesch Reading Ease score > 60; Flesch-Kincaid Grade Level ≤ 8 [14].
Action: If scores do not meet targets, proceed to Protocol 2 for systematic revision.

Protocol 2: Systematic Jargon Management and Simplification

Objective: To identify, categorize, and simplify or define necessary technical terminology.

Materials:

ICF draft
Standard medical dictionary
Plain-language thesaurus (e.g., NIH Plain Language Thesaurus)

Methodology:

Term Identification: Perform a line-by-line review of the ICF. Highlight every technical term, acronym, and complex phrase (e.g., "randomized controlled trial," "placebo," "adverse event").
Term Categorization: Classify each highlighted term into one of three categories:
- Category A: Replaceable. The term has a common, simple synonym (e.g., "hematoma" -> "bruise").
- Category B: Necessary, Requiring Definition. The term is essential but needs a plain-language explanation (e.g., "placebo" -> "an inactive substance, like a sugar pill").
- Category C: Necessary, Industry Standard. The term is universally used and understood in a specific context and may not require simplification (use sparingly).
Document Revision:
- For Category A terms, substitute the simpler synonym.
- For Category B terms, integrate a brief, clear definition immediately following the first use of the term in the text.
- Create a Glossary section at the end of the document listing all Category B terms and their definitions.
Validation: Re-run Protocol 1 after revisions to quantify improvement in readability scores.

Visualizing the Jargon Management Workflow

Research Reagent Solutions for Readability Analysis

Tool Name	Type	Function in Readability Research
Microsoft Word	Software Suite	Provides built-in functionality to calculate key readability metrics like Flesch Reading Ease and Flesch-Kincaid Grade Level after a grammar check [6].
Flesch Reading Ease (FRE)	Readability Formula	Assesses ease of reading based on average sentence length and syllables per word. Scores range 0-100; target >60 for lay comprehension [53].
Flesch-Kincaid Grade Level	Readability Formula	Converts the FRE score to a U.S. school grade level. A level of 8th grade or lower is the recommended target for ICFs [14].
SMOG Index	Readability Formula	Assesses readability by counting words of three or more syllables. It is considered a reliable tool for health-related materials [53].
Plain Language Thesaurus	Reference Tool	Provides simpler, alternative words and phrases for complex medical and scientific jargon to aid in document simplification.

The teach-back method is an evidence-based, interactive communication technique used to verify a participant's understanding of information by asking them to explain the content back in their own words [55] [56]. This method transforms the informed consent process from a passive signing event into an active, shared decision-making dialogue. It allows researchers to identify and rectify misunderstandings in real-time, thereby improving comprehension of complex clinical trial information [55] [57]. Within the broader thesis on informed consent form readability improvement strategies, teach-back serves as a crucial verbal complement to written plain-language revisions, addressing comprehension barriers that persist even after document-level optimizations.

Research across clinical and research settings demonstrates that teach-back significantly improves participant understanding, trust, and key study metrics.

Table 1: Quantitative Effects of Teach-Back on Key Outcomes

Outcome Measure	Effect of Teach-Back	Statistical Significance	Context
Knowledge Comprehension	Average improvement of 1 point on a 10-point quiz [57]	p = 0.048 [57]	Surgical Informed Consent
Physician/Researcher Trust	Significant increase in trust scores [57]	p = 0.046 [57]	Surgical Informed Consent
30-Day Readmission Rates	Reduction from 25% to 12% [56]	p = 0.02 [56]	Coronary Artery Bypass Graft
Participant Understanding	Higher scores on diagnosis, symptoms, and follow-up knowledge [56]	p < 0.001 [56]	Emergency Department Discharge
Implementation Time	Average increase of 2.45 minutes per consent interaction [57]	p = 0.001 [57]	Pre-operative Setting

Experimental Protocol for Implementing Teach-Back

Integrating teach-back into the informed consent process requires a structured methodology. The following protocol is adapted from successful clinical research implementations.

Objective: To verify and improve prospective participants' understanding of clinical trial procedures, risks, benefits, and alternatives using a standardized teach-back interaction.

Materials:

Approved, plain-language informed consent document.
Quiet, private room for discussion.
Teach-back checklist outlining key concepts for verification.

Procedure:

Segment and Explain: Break down the complex study information into small, manageable segments (e.g., primary purpose, procedures, potential risks, key benefits, alternative treatments). Explain each segment using plain, jargon-free language [58].
Request Teach-Back: Use a framing statement to place the focus on the clarity of your explanation, not the participant's intelligence. Ask the participant to explain the concept back to you in their own words [55] [58].
- Example Framing Statement: "I want to be sure I explained that clearly. Could you please tell me in your own words what you understand about the main procedures of the study?" [55] [58].
Assess and Clarify: Listen carefully to the participant's response.
- If the explanation is correct and complete, acknowledge this and move to the next segment.
- If there is any misunderstanding, omission, or error, gently correct the information using an alternative explanation. Avoid repeating the original phrasing [55] [56].
Re-check Understanding: Ask the participant to teach-back the clarified information to ensure the misunderstanding has been resolved [57].
Repeat Cycle: Continue this process of explaining, checking, and clarifying until all critical study concepts have been covered and understood.
Document the Interaction: Note in the research record that the teach-back method was used to verify understanding during the consent process.

Troubleshooting Guide: FAQs on Teach-Back Implementation

Q1: What should I do if a participant struggles to explain a concept during teach-back and becomes frustrated?

A: Reassure the participant that the goal is to ensure you have explained things well. Use a supportive tone: "This is complex information, and I appreciate you working through it with me. Let me try to explain it a different way." Simplify the language, use a visual aid, or use an analogy. The focus should remain on shared understanding, not testing the participant [56] [58].

Q2: How can I implement teach-back without significantly extending the consent appointment time?

A: The evidence shows an average increase of only 2-3 minutes per interaction [57]. Efficiency is gained by focusing teach-back on the most critical, high-risk, or complex elements of the study (e.g., dose-limiting toxicities, key procedures, main alternative to participation). Avoid using teach-back for every single detail.

Q3: A participant simply parrots back my exact words. How can I encourage them to use their own words?

A: Rephrase your initial request. Instead of "Repeat back what I just said," try more open-ended questions like, "What questions do you have?" or "How will you explain this to your family or your primary care doctor when you go home?" This prompts internal processing and genuine understanding [58].

Research Reagent Solutions for Communication Fidelity

Table 2: Essential Materials for Effective Informed Consent Communication

Item	Function in Consent Research
Plain-Language Consent Document	Serves as the foundational text, optimized for a 6th-8th grade reading level to reduce cognitive load before verbal discussion.
Teach-Back Checklist	Ensures standardized and consistent coverage of all key study elements (Primary Purpose, Procedures, Risks, Benefits, Alternatives) across all participants.
Visual Aids (Flowcharts, Diagrams)	Supports dual-coding of information (verbal and visual) to enhance comprehension and recall of complex study designs or timelines [59].
Digital Audio Recorder (with consent)	Allows for precise documentation of the consent conversation for quality assurance and later analysis of communication fidelity.
Multilingual Consent Materials & Translator	Eliminates language barriers, a prerequisite for valid informed consent and effective use of teach-back with non-native speakers [55].

The following diagram visualizes the cyclical, iterative process of the teach-back method within a clinical research consent interaction.

Diagram 1: Teach-back consent workflow.

Troubleshooting Guides and FAQs

Frequently Asked Questions

Q1: What is the maximum recommended reading grade level for an informed consent form? A: The recommended reading level for an informed consent document is no higher than an 8th-grade level [2]. This ensures the information is accessible to a wider population. Some technical studies might find this challenging, but this grade level is the target to strive for [2].

Q2: How can I effectively test if a consent form is comprehensible? A: Beyond readability scores, you should test the form's comprehensibility. Recommended methods include [11]:

Peer and Layperson Review: Have colleagues and individuals from a non-scientific background read the form.
Target Audience Testing: Test the form on individuals representative of your potential study population.
Comprehension Questionnaires: Use short questionnaires to test a participant's understanding of key concepts after they have read the form.

Q3: What are the most common linguistic pitfalls in consent forms? A: Common issues include using complex medical jargon, long and convoluted sentences, and the passive voice. Strategies for improvement include [11] [2]:

Replacing technical terms with common, lay language.
Using short, direct sentences and active verbs.
Dividing long sentences and limiting paragraphs to one central idea.
Using the second person ("you") to speak directly to the participant.

Q4: How can I present complex trial concepts like "randomization" clearly? A: Explain statistical concepts using simple, relatable analogies. For example, describe randomization for two groups as being "like the flip of a coin," and for more than two groups as "like drawing numbers from a hat" [2]. Always define the concept when it is first introduced.

Q5: Besides text, how can I improve the usability of a consent form? A: The visual design and structure are critical. Best practices include [2]:

Using at least a 12-point font and considering a larger size for specific audiences.
Using underline, bold, and boxes to highlight key points instead of italics or all capital letters.
Keeping paragraphs short and using bullet points where possible.
Incorporating photos, graphics, or tables to help clarify complex procedures.

Problem: Consent forms are too long and complex, acting as a deterrent to reading. Solution: Develop a shorter informed consent form that covers only the crucial points a reasonable person would want to understand [11]. Refer participants to appendices for additional, optional information. This reduces the initial burden and makes the core information less intimidating [11].

Problem: Low comprehension of consent information despite a "readable" form. Solution: Integrate additional informational meetings with a qualified counselor or patient educator beyond the initial discussion with the investigator [11]. A large amount of complicated information presented in a single meeting is difficult to absorb, and multiple sessions can significantly improve comprehension [11].

Problem: Ensuring translated consent forms are accurate and comprehensible. Solution: Avoid literal translations that lose the original meaning. Conduct peer review of the translated form that includes laypersons from the target language community to ensure the translation is not only accurate but also uses language that is easily understood by those with average education levels [11].

Problem: Participants do not remember or understand key concepts like the use of a placebo. Solution: Beyond signing the form, have the participant write the salient features in their own handwriting within the document [11]. For example, a statement such as, "I understand that I may receive a placebo instead of the active study drug," ensures these critical points are focused on and internalized.

Quantitative Data on Readability and Design

Table 1: Key Readability Metrics and Recommendations

Metric	Target / Recommendation	Rationale & Notes
Reading Grade Level	≤ 8th Grade Level [2]	Makes the document accessible to a broader population; required by many ethics committees.
Sentence & Paragraph Structure	Short sentences; one idea per paragraph [2]	Prevents complex sentence structures that hinder comprehension.
Font Size	At least 12-point [2]	Ensures text is legible for individuals with varying visual abilities.
Voice and Persona	Active verbs; second person ("you") [2]	Increases personal identification and makes instructions clearer.
Informed Consent Form Length	Shortened core form with appendices [11]	A shorter form is less daunting and helps participants focus on critical information.

Table 2: WCAG 2.2 Color Contrast Requirements for Visual Materials

This table summarizes key contrast requirements for creating accessible diagrams, charts, and other graphics included in patient-facing materials or research tools. These are based on Level AA standards [60].

Element Type	Minimum Contrast Ratio	Notes & Examples
Normal Text	4.5:1	Applies to most text. A contrast of 4.49:1 or below fails the requirement [60].
Large Text	3:1	Applies to text that is at least 18.66px and bold, or at least 24px [60].
User Interface Components	3:1	Applies to visual information required to identify states and boundaries of components [60].
Graphics & Charts	3:1	Applies to key information within non-text elements like charts and diagrams [60].

Experimental Protocols for Form Improvement

Protocol 1: Assessing and Improving Readability

Objective: To quantitatively and qualitatively evaluate an informed consent form and implement strategies to improve its readability and comprehensibility.

Methodology:

Initial Assessment:
- Quantitative Analysis: Use built-in software tools (e.g., Microsoft Word's Readability Statistics) to determine the Flesch-Kincaid Grade Level. Record the initial score [2].
- Jargon Identification: Manually scan the document to identify and list complex medical and technical terms (e.g., "randomization," "placebo-controlled").
Intervention - Form Revision:
- Simplify Language: Replace identified jargon with simple, common terms. For example, replace "principal investigator" with "study doctor" [2].
- Restructure Content: Break long sentences and paragraphs. Use bullet points and active voice. Add definitions for unavoidable complex concepts upon their first use [2].
- Visual Design: Implement a 12-point or larger font. Use bold and underlining for emphasis. Ensure ample white space [2].
Post-Intervention Assessment:
- Quantitative Re-test: Run the readability tool again to obtain a new grade level score.
- Comprehension Testing: Administer a short questionnaire to a small group of laypersons to test their understanding of key study concepts after reading the revised form [11].

Objective: To compare participant comprehension between a standard consent process and a structured process that includes a counselor and written exercises.

Methodology:

Study Arm Design:
- Control Group: Participants undergo the standard, one-meeting informed consent process with the investigator.
- Intervention Group: Participants undergo the standard process plus an additional information session with a qualified counselor and are asked to write key study points in their own words [11].
Measurement:
- All participants complete the same comprehension questionnaire after the consent process. The questionnaire should test understanding of critical elements like the study's purpose, procedures, risks, benefits, and the meaning of randomization and placebo [11] [40].
Analysis:
- Compare comprehension scores between the Control and Intervention groups to determine if the structured process with additional support leads to a statistically significant improvement in understanding.

Research Reagent Solutions: The Inclusive Designer's Toolkit

Tool / Resource	Function	Application in Consent Form Design
Readability Statistics Software (e.g., in Microsoft Word)	Calculates the reading grade level of a text document.	Provides a quantitative baseline and progress metric for simplifying consent form language [2].
Lay Terminology Glossary [2]	Provides common, non-medical equivalents for complex technical and medical terms.	Serves as a reference for replacing jargon with words that are easily understood by the general public [2].
Color Contrast Analyzer (e.g., based on WCAG)	Measures the contrast ratio between foreground (text) and background colors.	Ensures that any text, diagrams, or charts in the consent form are visually accessible to people with low vision or color deficiencies [39] [40] [60].
Comprehension Questionnaire	A short set of questions testing understanding of key study concepts.	Used as an evaluation tool to validate the effectiveness of the consent form and process [11] [40].

Visualizations for Inclusive Design Workflows

Diagram 2: Inclusive Design Principles

Measuring Success and Demonstrating the Impact of Readability Improvements

Accurate readability assessment is a critical first step in producing easily understandable consumer health information resources [62]. For researchers focused on informed consent forms, standard readability formulas provide a quantitative, repeatable method to ensure that complex medical and procedural information is accessible to a diverse participant population, thereby upholding the true spirit of informed consent.

Frequently Asked Questions

What is a readability formula and how does it work? Readability formulas are tools that estimate how easy a text is to read, usually expressed as a U.S. grade level or a score. They work by analyzing quantifiable text features, most commonly average sentence length and word complexity (often measured by syllables or word familiarity) [62] [63] [64].

Why can't I just use a standard grammar checker? While grammar checkers correct syntax, they do not systematically evaluate overall text complexity. Readability formulas provide an objective, standardized score that allows researchers to track and validate improvements in clarity, which is essential for ethical documentation like consent forms [63].

I used a formula, but my consent form still seems difficult to read. Why? Traditional formulas like Flesch-Kincaid rely heavily on word and sentence length. They may not fully capture difficulties arising from complex, unfamiliar medical terminology (e.g., "immunosuppressant") or dense procedural language. This is a known limitation, especially in the health domain [62].

Are there formulas designed specifically for medical or health texts? Yes. Research indicates that general formulas may underestimate the difficulty of health texts. Health-specific measures have been developed that incorporate semantic features (like term familiarity) and syntactic features (like parts of speech) for a more accurate assessment [62].

What is a good target readability score for an informed consent form? There is no universal standard, but best practice is to aim for the lowest grade level possible without sacrificing accuracy. For broad accessibility, many experts recommend aiming for a grade 8 level or below [63]. Always pair the score with user testing for validation.

Experimental Protocols for Readability Assessment

Protocol 1: Establishing a Baseline with General Formulas

This protocol uses established, widely-available formulas to get a quick, initial assessment of your document's readability.

Methodology

Text Preparation: Extract the full text of the informed consent form into a plain text file, removing any institutional headers, logos, or signature blocks that are not part of the explanatory content.
Tool Selection: Choose a readability tool that implements multiple formulas, such as the readability-formulas.com platform [64] or the WebFX Readability Test [63].
Analysis: Process the text through the tool to generate scores across several key formulas.
Interpretation: Calculate the average grade level from the formulas used to establish a baseline. Do not rely on a single score.

Expected Output A table of scores that provides a composite view of the text's complexity based on structural features.

Readability Formula	What It Measures	Baseline Score for Consent Form A
Flesch-Kincaid Grade Level	Average words per sentence, syllables per word [62] [63]	12.1
Gunning Fog Index	Sentence length, percentage of complex words [62]	14.8
SMOG Index	Number of polysyllabic words [62] [63]	13.5
Average Grade Level	---	13.5

Protocol 2: Health-Specific Readability Assessment

This protocol, inspired by academic research, provides a more nuanced analysis suitable for medical texts where jargon is unavoidable [62].

Methodology

Feature Identification: Beyond simple length, this method analyzes:
- Syntactic Features: The density of different parts of speech (nouns, verbs, prepositions) using natural language processing tools [62].
- Semantic Features: The familiarity of terms used, based on validated consumer health vocabularies that score how likely a term is to be understood by laypeople [62].
Distance Scoring: The feature profile of your consent form is compared against a benchmark of "easy-to-read" health texts. A "distance score" is calculated, representing how far your document deviates from the easy benchmark [62].
Tool Requirement: This typically requires more specialized software or research tools that incorporate health-term familiarity databases.

Expected Output A distance score where a higher number indicates a more difficult text. In research, this method successfully differentiated Electronic Health Records (more difficult) from consumer health texts (easier) [62].

Document Type	Average Distance Score	Interpretation
Consumer Health Text	2.11	Relatively easy
Informed Consent Form	Your Result	To be determined
Electronic Health Record	6.43	Difficult

Protocol 3: Comparative Readability Workflow

This integrated workflow uses multiple methods to thoroughly diagnose and guide the improvement of a consent form.

The Scientist's Toolkit

Research Reagent Solutions

Tool / Resource	Function in Readability Research
Python `textstat` library	A programmable library for calculating multiple readability formulas (Flesch-Kincaid, SMOG, etc.) at scale, ideal for analyzing large sets of documents [65].
Open Access & Collaborative (OAC) Consumer Health Vocabulary (CHV)	A database that provides familiarity scores for health terms. This is used in advanced, health-specific readability measures to assess semantic difficulty [62].
HITEx (Health Information Text Extraction)	A natural language processing tool used in research to extract syntactic features (parts of speech) from clinical text [62].
ReadabilityFormulas.com	A free online platform that processes text through seven popular readability formulas and provides a consensus score, useful for a comprehensive baseline analysis [64].
Hemingway Editor	A writing tool that highlights complex sentences, passive voice, and adverbs. It is useful for implementing revisions after a quantitative analysis identifies a high grade level [63].
CLEAR Corpus	A human-annotated benchmark dataset of text excerpts with "easiness" scores. It is used to validate and train new readability metrics, including those powered by LLMs [65].

Technical Support Center

Troubleshooting Guides

Problem: Even with a plain language template available, informed consent forms (ICFs) are still testing at a "difficult" readability level (grade 11 or above) [8].

Solution:

Verify Template Adoption: Confirm that researchers are using the most current institutional template. During one study period, only 52.1% of ICFs used the available template, which significantly impacted overall institutional readability scores [8].
Assess Comprehension Aids: Ensure the template includes a "Key Information" section with the voluntary nature of joining, total maximum enrollment time, major reasons to consider joining/not joining, and a brief description of study activities [8].
Implement Quality Control: Establish a pre-approval review process to check readability scores using standardized formulas (Flesch-Kincaid, SMOG, Fry Graph) before IRB submission [8].

Issue: Low Adoption of New Template Versions

Problem: Research teams continue using outdated consent form templates despite updated versions being available [8].

Solution:

Track Adoption Metrics: Monitor the percentage of ICFs using the current template. One institution improved adoption from 52.1% to 71.9% through targeted implementation efforts [8].
Provide Implementation Support: Offer training sessions, detailed instructions, and examples of successfully completed templates. Research indicates that users may not fully review instructions before beginning the consent form development process [66].
Highlight Regulatory Alignment: Emphasize how updated templates align with current FDA and Common Rule requirements, including the recent harmonization of key information expectations [67].

Frequently Asked Questions

Q: What readability level should we target for informed consent forms? A: Major research organizations, including the World Health Organization, recommend writing consent forms at the level of a local student of class 6th/8th (approximately grade 6-8 reading level) [68]. Studies show that plain language templates can reduce readability scores by three grade levels, moving forms from "difficult" (grade 11+) to "average" (grade 8-9) difficulty [8].

Q: How do we quantitatively measure improvements in consent form readability? A: Use standardized readability assessment protocols [8]:

Select 600-word samples from the beginning, middle, and end of each ICF
"Clean" samples by removing bullet points and extraneous punctuation
Analyze using multiple validated formulas (Flesch-Kincaid, SMOG, Fry Graph)
Average scores from the three formulas to determine mean readability
Categorize results as "easy," "average," or "difficult" based on established thresholds

Q: What specific template elements demonstrably improve readability? A: Evidence supports these key elements [8] [66]:

Organizational boxes with contrasting headers
Icons and color to visualize concepts
Bulleted text with ample white space
Concise key information section at the beginning
Plain language explanations of technical concepts

Quantitative Data Analysis

Readability Improvement Metrics

The implementation of structured informed consent form templates at an academic medical center demonstrated significant, quantifiable improvements in readability across multiple assessment periods [8].

Table 1: Longitudinal Readability Improvements Following Template Implementation

Time Period	Period Description	ICFs Assessed (n)	Mean Readability Grade Level	Readability Category	Statistical Significance (vs. P1)
P1 (2013-2015)	No plain language template available	84	11.10	Difficult	Not applicable
P2 (2016-2017)	After original template introduction	82	10.03	Difficult	p < 0.0001
P3 (2019-2020)	After updated template introduction	57	9.22	Average	p < 0.0001

Table 2: Readability Comparison by Template Usage

Template Usage	Template Description	ICFs Assessed (n)	Mean Readability Grade Level	Readability Category	Statistical Significance (vs. NT)
NT	No template used	139	11.33	Difficult	Not applicable
T1	Original plain language template	43	8.28	Average	p < 0.0001
T2	Updated template (Revised Common Rule)	41	8.54	Average	p < 0.0001

Categorical Improvement Analysis

The proportion of ICFs rated as "difficult" decreased substantially across the study periods: from 82.1% in P1 to 46.3% in P2, and further to 21.1% in P3 [8]. This demonstrates that template implementation not only improved mean readability scores but also reduced the prevalence of the most challenging consent forms.

Experimental Protocols

Readability Assessment Methodology

Objective: To evaluate the impact of ICF template updates on readability and determine if revised Common Rule requirements affect subjects' likelihood of reading ICFs with ease [8].

Materials:

Informed consent forms from investigator-initiated studies
Text samples (600 words each from beginning, middle, and end of ICFs)
Text cleaning protocol (removal of bullet points, extraneous punctuation)
Readability analysis software (Seven Formulas software, Micro Power & Light Co.)
Statistical analysis software (SPSS, IBM Statistics, v.21)

Procedure:

Sample Selection: A single staff member selects 600-word samples from the beginning, middle, and end of each ICF to ensure consistency [8].
Text Cleaning: Clean each sample using a standardized protocol:
- Remove bullet points and extraneous punctuation
- Modify abbreviations (e.g., removing period from "Dr. Smith")
- Standardize formatting for accurate software interpretation
Readability Analysis:
- Load cleaned samples into readability software
- Generate readability statistics using three validated formulas:
  - Flesch-Kincaid [8]
  - SMOG [8]
  - Fry Graph [8]
Score Calculation:
- Average scores from the three formulas
- Present as mean grade level rounded to nearest tenth
- Categorize into "easy," "average," or "difficult" levels [8]
Statistical Analysis:
- Compare mean readability scores across time periods using one-way ANOVA
- Assess changes based on template usage (none, original, updated)
- Calculate statistical significance with p < 0.05 threshold

Template Development Protocol

Objective: To create and validate plain language ICF templates that comply with regulatory requirements while optimizing readability [8].

Procedure:

Template Design:
- Apply plain language writing techniques
- Incorporate required Common Rule elements
- Add specific language for biospecimens and genetic information collection
- Include "Key Information" section with [8]:
  - Voluntary nature of participation
  - Total maximum enrollment time
  - Major reasons to consider joining
  - Major reasons not to join
  - Brief description of study activities

Usability Testing (for visual key information templates) [66]:
- Engage participants (principal investigators, research staff) in think-aloud protocols
- Collect feedback on template usability, acceptability, appropriateness, and feasibility
- Identify common challenges: interpreting instructions, condensing content, icon replacement
- Iteratively refine templates based on user feedback
Implementation Tracking:
- Monitor template adoption rates across submission periods
- Compare readability scores between template users and non-users
- Assess impact of template revisions on readability metrics

Workflow Visualization

Institutional Template Improvement Workflow

Research Reagent Solutions

Table 3: Essential Resources for Informed Consent Form Research and Development

Resource	Function	Application in Template Development
Plain Language ICF Template [8]	Standardized structure for consent forms	Provides baseline format complying with regulatory requirements while optimizing readability
Readability Assessment Software (Seven Formulas) [8]	Quantitative readability measurement	Generates scores using Flesch-Kincaid, SMOG, and Fry Graph formulas for objective comparison
Visual Key Information Toolkit [66]	Customizable template with icons and visual elements	Creates concise, visually enhanced key information pages to improve participant understanding
Regulatory Guidance Database (FDA, OHRP, NIH) [69] [70] [67]	Current ethical and regulatory requirements	Ensures templates align with latest standards, including key information and technology-specific disclosures
Statistical Analysis Software (SPSS) [8]	Data analysis and significance testing	Quantifies improvements and determines statistical significance of readability changes

While readability formulas provide a quantitative baseline for assessing informed consent forms, they are an insufficient proxy for true participant comprehension. Readability scores, such as Flesch-Kincaid or SMOG, primarily measure syntactic complexity—sentence length and syllable count—but cannot assess whether the core concepts, risks, and benefits of a research study are genuinely understood by the participant. A form can meet all grade-level recommendations while still failing to facilitate informed decision-making. This technical support center provides researchers, scientists, and drug development professionals with advanced methodologies and tools to move beyond basic metrics and ensure authentic comprehension.

Troubleshooting Guides and FAQs

Q1: Our consent form scores at an 8th-grade reading level, but participants still seem confused during the consent discussion. What is the next step? A1: A positive readability score does not guarantee comprehension. The next step is to implement a structured comprehension assessment using the Teach-Back Method or a Brief Structured Survey. These tools directly evaluate a participant's understanding of key study concepts, such as the voluntary nature of participation, primary procedures, and potential risks [13].

Q2: We need to simplify our consent form's language. What are the most effective plain-language techniques? A2: Effective simplification involves specific, actionable strategies:

Replace Jargon: Substitute technical terms with common words (e.g., "hypertension" becomes "high blood pressure").
Use Active Voice: Write in a direct, active style (e.g., "You may experience side effects" instead of "Side effects may be experienced by subjects").
Employ Visual Aids: Integrate simple diagrams, icons, and timelines to clarify complex procedures and study designs. Ensure all visuals adhere to color contrast standards for accessibility [15] [71].

Q3: How can we ensure our consent forms are accessible to participants with varying levels of health literacy? A3: Beyond plain language, adopt a modular consent structure. Instead of a single, monolithic document, present information in distinct, labeled sections. Furthermore, always involve members of your target population in the development and testing of consent materials through focus groups or usability testing to identify and rectify points of confusion [13] [12].

Q4: What are the key regulatory requirements for "Key Information" in consent forms under the Revised Common Rule? A4: The Revised Common Rule (46.116(a)(5)) mandates that consent forms begin with a concise and focused presentation of key information. This typically includes [13]:

The fact that consent is for research and participation is voluntary.
The purpose, duration, and principal procedures of the study.
Reasonably foreseeable risks and discomforts.
Potential benefits to the participant or others.
Appropriate alternative procedures or courses of treatment.

Quantitative Data on Readability and Comprehension

Study Metric	Pre-Intervention Baseline (n=217)	Post-Intervention (n=82)	Change
Mean Readability Grade Level	10th Grade	7th Grade	-3 Grade Levels
Percentage of Forms at ≤8th Grade Level	Not Reported	90.2%	658% Increase
Intervention Description	N/A	Provision of a plain-language informed consent template and investigator training [15]	N/A

Table 2: Essential Research Reagent Solutions for Comprehension Research

Reagent / Tool	Primary Function in Comprehension Research
Plain Language Consent Template	Provides a pre-structured framework that enforces best practices in language, organization, and formatting to improve baseline readability [15].
Readability Analysis Software	Automates the calculation of readability scores (e.g., Flesch-Kincaid, SMOG) to provide an initial, quantitative assessment of a form's complexity.
Teach-Back Method Protocol	A qualitative assessment tool where participants explain study details in their own words, allowing researchers to verify and correct understanding immediately [13].
Comprehension Survey Instrument	A structured questionnaire with multiple-choice or open-ended questions designed to objectively measure participants' grasp of specific, critical study elements.
Usability Testing Framework	A methodology for observing representative users as they interact with a draft consent form to identify navigational, terminological, and structural obstacles to understanding.

Experimental Protocols for Assessing Comprehension

Objective: To create and validate an informed consent template that significantly reduces reading grade level while maintaining all necessary regulatory elements.

Methodology:

Stakeholder Collaboration: Convene an interdisciplinary team including health literacy experts, IRB members, a research ethicist, and clinical investigators [15].
Iterative Drafting: Develop the template through successive drafts, assessing the readability of each iteration using multiple formulas (e.g., Fry Graph, Flesch-Kincaid, SMOG Index) to ensure adherence to plain language principles.
Participant Feedback: Conduct a focus group with individuals from the target participant population, including those with low health literacy. Use qualitative methods to gather feedback on clarity, layout, and overall understandability [15].
Finalization and Deployment: Finalize the template and make it available to investigators via the institutional IRB website. Provide complementary training sessions to IRB committees and research staff on its use and utility.

Protocol: Implementing the Teach-Back Method for Real-Time Comprehension Assessment

Objective: To verify participant understanding during the informed consent discussion.

Methodology:

Explanation: The researcher explains a key study concept (e.g., the right to withdraw) to the participant using plain language.
Soliciting Teach-Back: The researcher asks the participant to explain the concept in their own words, using a neutral prompt such as, "I want to make sure I explained this clearly. Could you please tell me back in your own words what you understand about [the concept]?" [13].
Assessment and Clarification: The researcher listens to the response to assess for accuracy and completeness.
Re-explanation: If the understanding is incorrect or incomplete, the researcher re-explains the concept using alternative language or methods.
Re-assessment: The cycle repeats until the participant demonstrates clear understanding, confirming that the information has been effectively communicated.

Visualizing Workflows and Relationships

Table 1: Readability Grade Levels by Trial Sponsor Type [72]

Sponsor Type	Mean Reading Grade Level	Number of Consent Forms Analyzed
Industry-Sponsored	13.6	45
NCI/NRG/GOG Foundation	13.3	42
Overall Average	13.0	103

Table 2: Readability Grade Levels by Disease Site (Gynecologic Oncology Trials) [72]

Disease Site	Mean Reading Grade Level	Number of Consent Forms Analyzed
Ovarian Cancer	13.0	41
Endometrial Cancer	12.0	21
Cervical Cancer	12.9	14
Vulvar/Vaginal Cancer	12.8	3
Multi-Disease Site/Basket Trials	13.0	24

A systematic review of 26 studies analyzing 13,940 informed consent forms across six languages found that 76.3% had poor readability, indicating this is a widespread, global issue transcending specific trial types or sponsors [1].

Experimental Protocols for Readability Assessment

Standardized Readability Assessment Workflow

The following diagram illustrates the core methodology for conducting a quantitative readability analysis of informed consent forms, as used in recent studies:

Core Readability Formulas and Their Calculations

Table 3: Standard Readability Formulas and Their Benchmarks [1]

Readability Index	Variables Assessed	Recommended Benchmark	Interpretation
Flesch-Kincaid Grade Level	Word complexity, Sentence length	≤ 8th Grade	Grade level needed to understand
Gunning Fog Index	Word complexity, Sentence length	≤ 8	Years of education needed
SMOG Index	Polysyllable word count	≤ 8	Years of education needed
Flesch Reading Ease	Word complexity, Sentence length	≥ 60 (Standard)	0-100 scale (Higher = Easier)
Automated Readability Index	Character/word ratio, Sentence length	≤ 8th Grade	Grade level estimate

Protocol for Comparative Readability Studies

A typical study design for comparing readability across sponsors and trial types involves [72]:

IRB-Exempt, Retrospective Analysis: Reviewing all therapeutic interventional clinical trials opened at an institution over a defined period (e.g., 5 years).
Inclusion/Exclusion Criteria: Including all consent forms from specified trial categories; excluding forms not publicly accessible or not in the primary language of analysis.
Stratification: Grouping consent forms by sponsor type (Industry, NCI/NRG/GOG, Investigator-Initiated) and disease site/trial type.
Statistical Analysis: Using unpaired t-tests to compare mean readability scores between sponsor types and disease sites, with statistical significance set at p<0.05.

The Scientist's Toolkit: Readability Research Reagents

Table 4: Essential Tools for Readability Research and Improvement

Tool / Resource	Function	Application in Readability Research
Readability Studio Professional Edition [72]	Comprehensive software calculating multiple readability indices	Primary quantitative analysis in research settings
Microsoft Word Readability Statistics [5] [2]	Built-in Flesch-Kincaid scoring within spell check	Quick, accessible grade-level checks during document drafting
Automatic Readability Checker [5]	Free online readability calculator	Initial screening and validation
Plain Language Thesaurus [5] [2]	Word replacement resource for simplifying medical/scientific jargon	Drafting and revising consent forms to reduce complexity
CDC's "Everyday Words for Public Health Communication" [5]	Sector-specific plain language guide	Finding context-appropriate simple alternatives for technical terms

Frequently Asked Questions (FAQs) and Troubleshooting Guides

Answer: The American Medical Association (AMA) and National Institutes of Health (NIH) recommend that patient-facing materials, including informed consent forms, should be written at a 6th to 8th-grade reading level [72] [2]. This benchmark is based on the average reading age for adults in the United States and ensures accessibility for the vast majority of the population. Current data shows most forms far exceed this, averaging at a 13th-grade (college) level [72].

Troubleshooting Guide:

Use Simple Words: Replace words with ≥3 syllables with simpler alternatives (e.g., "use" instead of "utilize," "about" instead of "approximately") [5].
Apply Active Voice: Use "We will measure your blood pressure" instead of the passive "Your blood pressure will be measured by..." [5].
Write Short Sentences: Break long, multi-clause sentences into one thought per sentence [2].
Use Visual Aids: Replace dense paragraphs of procedures with tables, bulleted lists, and flowcharts to present complex information more clearly [73] [74].
Leverage eConsent Platforms: Use interactive electronic consent with embedded definitions, videos, and graphics to explain complex concepts without overloading the text [74].

Answer: Yes, empirical evidence supports this. A large, multinational randomized trial compared a standard consent form (5,927 words, Grade 10.3 level) with a concise version (1,821 words, Grade 9.2 level). The study found no significant difference in participant comprehension of key concepts like randomization between the two forms, demonstrating that concise forms are non-inferior while being significantly shorter and more accessible [73].

FAQ 4: What are the most effective formatting strategies to enhance readability?

Answer:

Font and Layout: Use minimum 12-point, sans-serif fonts (Arial, Calibri) with left-justified, right-ragged formatting and 1-inch margins to create visual cues and white space [5] [2].
Emphasis: Use bold or italics sparingly to highlight critical points. Avoid overusing all capital letters [5].
Structured Tables: Use tables to summarize study procedures and visits, which reduces repetition and length while improving clarity [74].
Consistent Terminology: Use "study drug" for investigational products, not "treatment" or "therapy." Use "you" and "we" to personalize the document [2].

Answer: Consider using separate, tailored consent forms for distinct cohorts or treatment arms. This allows language, procedures, and risks to be specific to the participant's situation, reducing confusion from irrelevant information. The main challenge is maintaining multiple documents, so this is best when cohort procedures differ significantly [74]. For less divergent groups, a single document with clear conditional sections is more manageable.

Answer: eConsent platforms that incorporate interactive elements like embedded dictionaries, videos, graphics, and quizzes can significantly improve comprehension and satisfaction. They support different learning styles (visual, auditory) and allow participants to review information at their own pace. However, systems must be 21 CFR Part 11 compliant for FDA-regulated trials [74].

Conclusion

Improving the readability of informed consent forms is not merely a stylistic exercise but a fundamental requirement for ethical and valid clinical research. By adopting a systematic approach that combines plain language, targeted readability goals, thoughtful formatting, and robust validation methods, researchers can transform ICFs from barriers into bridges for participant engagement and understanding. The future of responsible research demands that we move beyond compliance checkboxes and prioritize true participant comprehension, which is essential for upholding the principle of respect for persons, ensuring informed decision-making, and upholding the integrity of the scientific enterprise.

Improving Informed Consent Form Readability: A Data-Driven Guide for Clinical Researchers

Improving Informed Consent Form Readability: A Data-Driven Guide for Clinical Researchers

Abstract

The Readability Crisis in Informed Consent: Why It Matters for Ethical Research

Defining Readability and Its Direct Impact on Participant Comprehension

Frequently Asked Questions (FAQs)

Troubleshooting Guides

Quantitative Data on ICF Readability

Experimental Protocols for Readability Improvement

Readability Improvement Workflow

The Scientist's Toolkit: Essential Reagents for Readability

Frequently Asked Questions

Troubleshooting Guides

Guide 1: Diagnosing Readability Issues in Your Consent Form

Guide 2: Implementing a Strategy for Readability Improvement

The Scientist's Toolkit: Essential Reagents for Consent Form Readability

FAQs: Readability and Regulatory Compliance

Troubleshooting Guides

Problem: High Readability Grade Level

Problem: Poor Participant Comprehension

Problem: Low Adoption of Plain Language Practices by Researchers

Experimental Protocols and Data

Quantitative Data on Readability Improvement

Detailed Methodology: Readability Assessment

Visual Workflow: Improving Consent Form Readability

The Scientist's Toolkit: Research Reagent Solutions

Troubleshooting Guides

Guide 1: Diagnosing and Remedying Poor Participant Comprehension

Guide 2: Addressing Low Enrollment and High Dropout Rates

Frequently Asked Questions (FAQs)

Experimental Protocols

Protocol 1: Implementing a Plain Language Consent Template

Protocol 2: Testing Comprehension Using a Simplified vs. Standard Form

Logical Workflow Diagram

Research Reagent Solutions

Actionable Strategies for Writing Clear and Compliant Consent Forms

Troubleshooting Guide: Common Jargon-Related Issues

Problem: My informed consent forms are too long and complex.

Problem: I need to use a precise technical term, but it may not be widely understood.

Frequently Asked Questions (FAQs)

What is the difference between necessary technical terminology and bad jargon?

Is it acceptable to use some jargon in scientific writing?

Won't simplifying my language make my work seem less academic?

What are some practical alternatives to common complex words?

What readability standard should I aim for in informed consent forms?

Experimental Protocols for Readability Improvement

Protocol 1: Usability Testing for Informed Consent Forms

Protocol 2: Testing Participant Comprehension

Visualizing the Plain Language Writing Workflow

The Scientist's Toolkit: Key Reagents for Readability

What are the target readability scores for informed consent forms?

Why is an 8th-grade reading level the target for informed consent?

How do I measure the readability of my documents?

Flesch-Kincaid Formula

SMOG (Simplified Measure of Gobbledygook) Formula

Step-by-Step Measurement Protocol

What are the best practices for improving consent form readability?

Research Reagent Solutions for Readability Improvement

Frequently Asked Questions (FAQs)

Our IRB requires precise legal and medical terminology. How can we simplify the form without losing necessary meaning?

Does the FDA have specific requirements for consent form readability?

Are there any parts of the consent form where readability is most critical?

Troubleshooting Guides and FAQs

How can I quickly check if my consent form is easy to read?

My consent form is too long and text-heavy. How can I break it up?

What is the simplest way to improve my consent form's language?

Are there tools to help me build a compliant and clear consent form?

How can I validate that my formatting changes actually improve understanding?

Experimental Protocols and Data

► Protocol 1: Longitudinal Readability Assessment

► Protocol 2: Cross-Sectional Readability Evaluation

Visual Workflows and Aids

► ICF Readability Assessment Workflow

► Two-Part Consent Document Structure

Quantitative Assessment of Readability Improvements

Longitudinal Readability Outcomes

Template-Driven Readability Enhancement

Experimental Protocols for Readability Assessment

Standardized Readability Evaluation Methodology

Readability Improvement Workflow