Participant Health Literacy

Participant health literacy is the degree to which a prospective or enrolled research participant can find, understand, and act on the information needed to make a voluntary decision about joining a study and to follow study procedures once enrolled. In practice, a research team is designing for participant health literacy whenever it (1) writes consent forms, recruitment materials, and result-summary/plain-language-summary documents at a reading level and format the target population can actually process (commonly benchmarked to roughly a 6th-8th grade level, though neither the Common Rule nor FDA regulations set a numeric threshold -- both simply require information 'understandable to the subject'), and (2) actively checks comprehension rather than assuming it, most often via the teach-back method: asking the participant to restate key study facts (purpose, main procedures, risks, voluntariness, right to withdraw) in their own words before consent is finalized. A document or process only counts as addressing health literacy if both elements -- accessible language AND a comprehension check -- are present; a well-simplified form that nobody ever asks the participant to explain back is a partial, not complete, application of the concept.

ByCASRAI Editorial Board

· Last updated 23 Jul 2026

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Worked examples

Is an instance

A study team drafts its informed consent form at an approximately 6th-8th grade reading level, replaces jargon ('randomization,' 'placebo-controlled') with plain-language explanations, and trains the person obtaining consent to ask the participant to describe, in their own words, what will happen during the study and that participation is voluntary -- documenting that the teach-back was completed before the participant signs.

Is an instance

A funder or journal requires a plain-language summary of study results, written for a general public audience without technical terminology, distributed to participants after study completion -- extending health-literacy principles from the consent stage into the results-communication stage.

Looks similar, but isn't

Not an instance

A 14-page consent form written at a graduate reading level that technically satisfies 45 CFR 46.116's 'language understandable to the subject' requirement on paper, but where the study team never checks whether the participant actually understood it, is not an application of participant health literacy as the concept is used in practice -- regulatory compliance and demonstrated comprehension are not the same thing.

Participant health literacy is the applied, research-specific form of general health literacy: it asks not just whether someone can read a document, but whether a prospective or enrolled study participant can understand what participation actually involves well enough to make a genuinely informed, voluntary decision — and to follow study procedures correctly afterward.

Why it is treated as its own concept

The Common Rule (45 CFR 46.116) and FDA’s parallel consent regulation (21 CFR 50.20) both require that information be presented “in language understandable to the subject,” but neither sets a numeric reading-level threshold. In practice, IRBs and institutions commonly operationalize this as a target of roughly a 6th-8th grade reading level (via Flesch-Kincaid or a similar readability measure), because the general adult population’s literacy skills are lower than researchers often assume: the 2003 National Assessment of Adult Literacy (NAAL), conducted by the U.S. Department of Education’s National Center for Education Statistics, found that only about 12% of U.S. adults had proficient health literacy, with more than a third scoring basic or below-basic.

That gap is why health literacy is treated as a distinct design consideration layered on top of the baseline legal requirement for an ICF (Informed Consent Form), rather than something automatically satisfied by an IRB-approved consent document. A form can be legally compliant and still fail to actually inform the person reading it.

The two components: readable language and confirmed comprehension

1. Plain-language design

This covers consent forms, recruitment flyers and scripts, protocol-related instructions given to participants, and — increasingly — plain-language summaries of study results distributed after a trial ends. Common techniques include short sentences, active voice, common words in place of technical or Latinate terms, larger type and white space, and visual aids (diagrams, icons, or simple tables) to support text rather than replace it.

2. Teach-back (confirming understanding)

Plain language alone only addresses whether a document is readable, not whether a specific individual actually understood it. The teach-back method closes that gap: the person obtaining consent asks the participant to explain, in their own words, key facts about the study — its purpose, what will happen to them, the main risks, that participation is voluntary, and that they can withdraw at any time — rather than simply asking “do you have any questions?” or “do you understand?”, both of which are known to be poor comprehension checks because participants tend to answer them affirmatively regardless of actual understanding. Teach-back is applicable beyond the initial consent conversation too — at re-consent, and at any point in a study where new information needs to be understood and acted on (a protocol amendment, a new procedure, a safety update).

Where this shows up in practice

Consent form drafting and IRB review — readability is a common IRB comment on submitted ICFs, alongside the substantive elements required under 45 CFR 46.116/21 CFR 50.25.
Recruitment materials — flyers, scripts, and study websites benefit from the same plain-language and visual-design principles as the consent form itself.
Populations with additional access barriers — health literacy considerations compound with language barriers for participants whose first language is not the one materials were drafted in; see eConsent for how electronic consent platforms can layer multimedia and interactive comprehension checks (including teach-back-style quizzes) onto the same underlying document.
Results communication — plain-language summaries of trial results, increasingly expected by funders and required under some EU regulatory frameworks, extend health-literacy principles past enrollment to the end of a participant’s involvement in a study.

Related resources

The Multi-Regional Clinical Trials Center of Brigham and Women’s Hospital and Harvard (MRCT Center) maintains a dedicated Health Literacy in Clinical Research program with practical tools, including guidance on applying teach-back throughout the clinical trial lifecycle, not only at initial consent.

For the mechanics of building a compliant consent form itself, see the Informed Consent Checklist for Researchers and the Informed consent and ICF (Informed Consent Form) dictionary entries.

Use in your systems

JATS XML <role> element

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Schema.org DefinedTerm (JSON-LD)

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