How to Write an Informed Consent Form Participants Can Actually Understand

How do you make a consent form understandable without oversimplifying the research?

Researchers often face an awkward writing problem. A consent form must contain enough information to support an informed decision, yet adding more detail can make the document harder to understand.

The solution is not simply to shorten everything or replace every technical term with a simpler word. An understandable consent form needs to communicate the information that matters, explain unavoidable technical concepts, organize information around the participant's decision, and use language appropriate for the people being asked to participate.

That makes consent writing a communication problem as much as a documentation problem.

Write for the participant's decision, not for the research protocol

How to turn research information into participant information

A research protocol and a consent form serve different readers. The protocol explains and justifies the research to reviewers and other researchers. The consent form helps a potential participant make a decision.

Copying protocol language into the consent form therefore tends to solve the wrong writing problem. The relevant question is not whether another researcher would understand the document. It is whether the people you plan to recruit can understand what participation means for them.

Start with what participants most need to know

Do not make participants search through several pages before discovering what they will actually be asked to do.

Under the revised U.S. Common Rule, for research governed by its general informed-consent requirements, consent begins with a concise and focused presentation of the key information most likely to help a prospective participant understand why they might or might not want to participate. The regulations also require the consent information as a whole to be organized and presented in a way that facilitates understanding rather than merely providing isolated facts.

That regulatory requirement is not universal to every jurisdiction, but the communication principle is broadly useful: prioritize information according to its importance to the participant's decision.

For many studies, participants will want to establish fairly quickly that this is research, why they are being invited, what they will do, how long participation will take, what significant risks or burdens they may face, whether they can reasonably expect any benefit, and whether participation is voluntary. The exact information participants need before consenting depends on the study and the framework governing it.

Use ordinary words when ordinary words are accurate

Technical vocabulary is useful among specialists because it compresses complicated ideas into precise terms. That advantage disappears when the reader does not know what the terminology means.

OHRP advises that ordinary language should replace technical terminology where possible. Its examples include describing an "upper extremity" as an arm and explaining "venipuncture" as taking blood from the arm with a needle.

The second version is not necessarily less accurate. It simply does less interpretive work for the researcher and more for the reader.

Explain technical terms that cannot reasonably be removed

Some terminology is necessary. Participants in a randomized trial, for example, may need to understand random assignment. Replacing the term with something vague can reduce rather than improve understanding.

In those situations, explain the concept when it first appears. A participant usually does not need the disciplinary history of randomization, but they may need to know that assignment is determined by chance rather than chosen by them or their clinician.

Plain language should not mean imprecise language.

Write concretely about what will happen

Abstract descriptions make participants translate research language into lived experience. Whenever possible, tell them what they will actually do.

"Data will be collected at multiple time points" is less useful than explaining that the participant will complete one 20-minute questionnaire today and another questionnaire approximately four weeks later.

The same principle applies to procedures, recordings, biological samples, follow-up contacts, interventions, and use of identifiable information. Concrete descriptions help participants imagine participation before agreeing to it.

Organize information around meaning, not regulatory categories

A form can contain every required element and still be difficult to follow if the information appears as disconnected statements.

Information that answers the same participant question should generally appear together. What will happen? How long will it take? What are the important risks? What happens to my information? Can I stop? Who can I contact?

This does not mean every consent form needs those exact headings. It means the structure should help readers form a coherent picture of participation.

Make risks specific enough to inform a decision

A statement such as "there may be risks associated with participation" tells the participant almost nothing. When foreseeable risks or discomforts need to be disclosed, describe them in terms that allow the participant to understand their nature and relevance.

At the same time, avoid making every conceivable inconvenience sound equally important. A long undifferentiated inventory can obscure the risks that are most consequential to the decision.

Do not exaggerate benefits

Consent language should distinguish potential benefits to the participant from broader benefits to science, services, policy, or future populations. A participant completing a survey may receive no direct personal benefit even though the study could contribute useful knowledge.

Avoid implying that benefit is guaranteed when it is uncertain. This is particularly important in health research, where participation in research should not be presented as though an experimental intervention were established treatment.

Make voluntariness concrete

"Participation is voluntary" is useful, but sometimes participants need to know what that means in their circumstances.

A student recruited through a course may wonder whether refusal will affect a grade. An employee may worry about their supervisor. A patient may wonder whether declining will affect clinical care. When such concerns are reasonably foreseeable, address them clearly and accurately rather than relying on the word "voluntary" to do all the work.

Write for the people you are actually recruiting

There is no single vocabulary level that makes a consent form universally understandable. Age, language proficiency, educational background, familiarity with research, cognitive abilities, cultural context, and the complexity of the study can all affect communication.

OHRP specifically advises attention to language and literacy when designing consent materials. The 2024 Declaration of Helsinki likewise calls for information in plain language and attention to the individual participant's information and communication needs in medical research.

Translation also deserves more than word substitution. A grammatically accurate translation can remain confusing if the underlying document was difficult to understand in the first place.

Do not use readability scores as proof of comprehension

Readability formulas can identify some features of difficult prose, particularly sentence and word complexity. They cannot establish that a participant understands randomization, confidentiality limitations, data sharing, withdrawal consequences, or a complicated risk.

A document can achieve a desirable reading level while remaining conceptually confusing. Conversely, an unavoidable technical term may increase a readability score even when it has been explained well.

Use readability measures, when useful, as diagnostic tools rather than certificates of comprehensibility.

Length and understanding are not the same thing

A short form can omit important information. A long form can bury it.

The goal is therefore not minimum length but useful information density. Include what participants need and what the applicable framework requires, explain it adequately, and remove repetition or technical detail that does not improve the participant's decision.

This becomes especially important when deciding how much information belongs in a consent form. More information does not automatically produce a better-informed participant.

From protocol language to participant language

The revision works because it changes the perspective of the writing. Instead of describing the study as a researcher would describe the methodology, it helps the participant anticipate what participation will actually involve.

Common mistakes when writing consent forms

Edit the consent form from the participant's side of the table

Once you have drafted the required content, stop reading the form as its author. Read it as someone who has never seen the protocol.

Can you tell quickly why you are being invited? Can you picture what will happen? Do you know what might make you hesitate? Can you identify what happens to your information? Is it obvious that you can refuse?

Where feasible, consider asking someone unfamiliar with the study to read the draft. OHRP notes that some IRBs use lay members or members of the proposed participant population to identify language they do not understand. That kind of review can reveal assumptions invisible to people who have spent months immersed in the protocol.

And remember the boundary: improving the document is not the same as demonstrating that participants understood it. Whether and how to assess actual participant understanding is a separate question.

Before submitting your consent form for review

Questions about writing understandable consent forms

A good consent form helps someone make a decision

How to Cite This Guide

This guide is intended to be read, shared, and used in research, teaching, and academic work. If you draw on its ideas, explanations, or other content, please acknowledge the source by citing the guide. Doing so gives appropriate credit and helps your readers locate the original resource.