Introduction

The clinical trials industry relies heavily on print and digital materials for patient recruitment and retention. To be effective, these materials must connect with the audience. There are many ways to make this connection, from writing clinical trial materials to designing them.

One common pitfall is writing at a reading level that is too high. Additionally, failing to use clear communication and plain language can negatively impact the health literacy of materials for participants. Overlooking the significance of readability can have the unintended consequence of hindering participation in clinical trials.

It’s easy to make this mistake. Our audience often has a reading level that is lower than our own. As life science professionals, we tend to communicate in precise language. When we transition our study from protocol to potential participants, we need to simplify our language to ensure broader readability and improve health literacy. Big words can be sublimely precise, but using them in participant materials puts you in danger of losing your reader. Reducing the reading level of our pieces when writing clinical trial materials for participants is important.

If writing at a broader reading and health literacy level doesn’t come naturally to you, read on. (And a quick note – here we are addressing materials for adult audiences, not pediatric studies.)

Step 1

Write clinical trial materials at the reading and health literacy level you most easily write to. You will look for ways to improve these later.

Trying to accomplish too much can be stifling. Begin by getting the necessary information down on paper, and don’t worry about the reading and health literacy levels. Write each sentence the way you would normally, in a way that comes naturally to you.

As you move from rough draft to first draft — changing, fixing, and improving — perform all your necessary wordsmithing as usual. Again, don’t concern yourself with the readability of the materials. That will come later.

And now that your first draft is done, it is time for the next step.

Step 2

Translate your text into participant-friendly language.

Once you have written a good first draft, check the readability statistics and evaluate according to the reading level of your audience. According to the National Literacy Institute, adults in the U.S. have an average reading level of 7th – 8th grade. However, 54% have literacy below a sixth-grade level.

To check the reading level when using Microsoft Word, reading level statistics pop up at the end of the spelling and grammar check feature. This gives you raw data about your document, including the number of words, the average number of words per sentence, and the Flesch-Kincaid Grade Level.

Next, examine your perfectly crafted sentences for opportunities to broaden the readability level. What reading level should you aim for? Is that level sufficient, or should you aim lower? There are plenty of people on either side of average, and aiming more broadly can help you reach a bigger audience. We find that sixth grade often feels about right.

Now, examine the health literacy of your writing. According to the U.S. Department of Health and Human Services’ (HHS) Healthy People 2030 initiative, health literacy involves the information and services that people need to make well-informed health decisions. Health literacy has several aspects, including personal, organizational, digital, and numeracy. Here, we focus on personal health literacy, defined as the degree to which individuals can find, understand, and use information and services to inform health-related decisions and actions for themselves and others.

Read on for tips to enhance the clarity and understanding of writing for participant-facing materials. Keep in mind that a patient flyer is likely to contain less medical jargon than, say, a visit-by-visit guide or a participant diary. Some documents will require more work.

Ways to make participant-facing clinical study materials more understandable:

Medical terms:

Are they known to your audience? For example, if your study is recruiting sciatica patients, your audience may know what sciatica means. So it stays, but you may want to add an explanation in plain language terms, such as sciatica (pain in the back, hip, and outer side of the leg), to ensure clarity. If your study is the lung disease pneumonoultramicroscopicsilicovolcanoconiosis, there is no getting around that, either. It stays, too, but a short explanation may be helpful to the reader. Also, consider whether abbreviations or acronyms will be understandable to your audience, and be sure to write them out the first time (e.g., hypertension [HTN]).

Look for things that are long:

• Long words? Reduce the syllables.
• Long sentences? Reduce the number of words.
• Long paragraphs? Reduce the number of sentences.

Examples of common non-medical words that can be changed to impact readability:

• Participate: take part
• Reduce: lower
• Confirm: make sure
• Evaluate: find
• Modify: change
• Determine: find out

Examples of medical terms that can be changed or explained in a few words to improve clarity:

• Treatment-resistant: Treatment doesn’t work well
• Effectiveness/efficacy: How well the [drug or procedure] works
• Titrate: Change the dose of a medicine

It’s OK to retain a big word if it is necessary – just define it. Here is an example:

Shots will be given sequentially (one after the other).

A bullet list is a good way to rework a paragraph into distinct thoughts. Here is an example of changing some words and moving to a bullet list format. I have also added a line at the end that defines placebo:

Original paragraph:

Participants will be randomized (like flipping a coin) into two treatment arms. One arm will receive the study drug, and the other arm will receive a placebo.

Revision:

People who take part in this study will be placed by chance (like flipping a coin) into 1 of 2 groups:

• One group will receive the study drug
• One group will receive a placebo

A placebo looks like the study drug but contains no active medicine.

The revision takes up more space, but the information is communicated in a clearer way.

A note about numbers. The standard rule in writing is to spell out numbers one through nine and use Arabic numbers for 10 and above. Let’s agree that we can break that rule for ease of readability in our patient materials.

Step 3

Make sure you didn’t take it too far.

Before you consider your masterpiece finished, give it a fresh look. Did you reduce the reading level too severely? It’s possible to overdo it. As you read through, ask yourself:

Did I change or lose the meaning of a word?

For example, changing migraine to headache is probably too vague. The term “migraine” may need a non-technical definition instead.

Did I go too far, perhaps alienating skilled readers and patients who are very knowledgeable about their indication?

For example, when writing clinical trial materials for a study enrolling patients who have already experienced a few rounds of chemotherapy similar to the study drug, the reader has a knowledge base and can most likely handle text with fewer explanations.

Did I leave out any important points?

For example:

Original sentence: It is possible the study drug will help patients recover from [disease being studied] more quickly.

Revision to reflect the protocol more completely: Study doctors will see if the study drug safely helps participants recover more quickly from [disease being studied] and see how well their bodies handle it.

Final thoughts

1. When writing clinical trial materials, don’t let others sabotage your efforts. Your text is likely to go to others for their approval and/or edits. Let them know your text is written for patient-friendly readability using plain language. Ask that they keep that in mind when making any changes.
2. It’s up to you. Even though that reading level number can stay the same, go up, or go down as you make text changes, don’t give it too much control. It’s a guide. You be the judge of your text.
3. Beginning with a first draft that isn’t at your audience’s reading level may seem like an unnecessary extra step. But give this method a try, and you may find that it actually streamlines the process and makes your final draft stronger.

Have you found ways to make your writing more patient-friendly? Please share your tips in the comment box below. Also, be sure to check out our blog about using plain language for writing participant-facing clinical trial materials.

Updated: 07 September 2025, 28 JULY 2022