Why diversity in clinical trials matters

Who takes part in research shapes what we learn

A clinical trial can only tell us how a treatment works in the kinds of people who took part.

If most participants share the same age range, sex or background, doctors have less information about how the treatment works for everyone else. That gap matters most for conditions that affect some communities more often or more severely.

Why it matters for safety and effectiveness

People can respond differently to the same medicine because of age, sex, other health conditions, genetics, diet or environment.

Some of these differences change the right dose or the side effects to watch for. When a group is missing from research, those differences may only be noticed after a treatment is already in wide use.

Why under-enrollment happens

Under-enrollment usually has practical causes, not a lack of interest.

Common reasons include study sites being far from where people live, visits during working hours, travel and childcare costs, strict eligibility rules, materials offered in only one language, and doctors not mentioning trials to every patient. Past abuses in research, such as the Tuskegee study, have also left understandable mistrust in some communities.

What is changing

Since 1993, US law has required research funded by the National Institutes of Health to include women and members of minority groups unless there is a clear reason not to.

In 2022 Congress passed a law requiring sponsors of many late-stage drug and device trials to give the FDA a plan for enrolling a more representative group of participants. How these plans are applied is still developing. Many studies are also adding remote visits, travel help and materials in more languages.

What this means for you

You never have to join a trial to help others, and choosing not to take part is always a valid decision.

If you are interested, it is reasonable to ask the study team where the study is enrolling, whether visits can be flexible, what costs are covered, and whether materials are available in your language.

How RightFit approaches this

RightFit lists recruiting studies by condition and city so more people can see what is available near them.

We never ask for your race, ethnicity or any other personal details, and our eligibility checker runs only in your browser. Each listing shows who can join based on what the study itself publishes.

Browse related trials

• Prostate Cancer trials
• Sickle Cell Disease trials
• Type 2 Diabetes trials
• Hypertension trials

Quick answers

Why does diversity matter in clinical trials?

A clinical trial can only tell us how a treatment works in the kinds of people who took part.

Can people respond differently to the same medicine?

People can respond differently to the same medicine because of age, sex, other health conditions, genetics, diet or environment.

Why are some groups under-represented in trials?

Under-enrollment usually has practical causes, not a lack of interest.

Are there rules about who must be included in research?

Since 1993, US law has required research funded by the National Institutes of Health to include women and members of minority groups unless there is a clear reason not to.

Do I have to join a trial to help?

You never have to join a trial to help others, and choosing not to take part is always a valid decision.

Sources

• NIH — Inclusion of Women and Minorities as Participants in Research
• FDA — Diversity Action Plans to Improve Enrollment of Participants
• NIH — Clinical Research Trials and You: The Basics