Why It’s Important That a Variety of People Participate in Clinical Research

Clinical research is the careful study of people’s health and diseases. For decades, clinical research studies mostly included the same types of people and did not reflect the broader human population. Today, researchers realize that if studies do not include men and women or people of different racial and ethnic backgrounds, the results will not apply to everyone.

Through clinical trials, scientists have learned that people of different sexes, ages, races and ethnic groups respond uniquely to medications and treatments. Scientific studies and results have provided insight and clarity about how and why these differences occur. This knowledge highlights why the variety of participants in clinical research is important and leads to better health care outcomes for everyone.

Consider a disease like cancer, which could potentially affect every type of person. How could scientists develop a cancer treatment that helps everyone if specific groups are left out of clinical research studies? In truth, they cannot create an effective treatment for people of color, children or older adults, or women, unless those groups participate in studies. 

Making Research Results Useful for More People

Generalizability means how well research findings can be applied to most people most of the time. External validity means how well the results of a study apply to people, places or situations outside of the study itself. How well a study’s results apply to the real world or to other people shows its external validity. When a study can be generalized enough to apply to the broader population, it means the results can apply to many different people, not just those who were in the study. To make this happen, researchers need to include a wide mix of people from different backgrounds, chosen at random.

Representing Different Backgrounds

Different groups of people can react differently to medicines. But many of these groups, including women, children, and minority groups, have not been included enough in past research. This makes it harder to know if treatments will work for everyone.

Over the last 25 years, science and government groups have worked to fix this by making research more inclusive and diverse. By including people from all backgrounds in studies, scientists can create better, safer, more effective treatments that work well for everyone.

Impact on Research Outcomes and Effectiveness

Including people from different backgrounds in research also helps scientists find side effects and safety issues affected by things like genetics, age, and sex.

• Example number one: Researchers have learned through studies that men and women respond differently to antidepressant medications. 
• Example number two: Research studies discovered that people of European descent and those with African ancestry respond differently to high blood pressure medicine.

Scientists can better understand how and why people respond differently to treatments by studying people from all backgrounds. A person’s lifestyle and living environment can also affect treatment response. Study volunteer populations should include active and sedentary people, people who work in different careers, and people living in urban and rural areas. Therefore, where study participants live and work should also vary to reflect true diversity.