Back To Blog

What Does Diversity Mean in Clinical Trials?


The lack of diversity in clinical trials is a major issue that scientific research is battling today. The ethical inclusion of diverse participants in clinical trials is indispensable to maintaining the rigor and generalizability of research results. And there are more reasons to enhance the diversity of clinical trial populations. But what is diversity in clinical trials?

The general definition of diversity is the presence of variations of different characteristics in a group of individuals or simply the state of being diverse. Clinical trial diversity is the intentional inclusion of a diverse patient population as participants. It means including participants who differ from each other based on factors such as:

  • Race
  • Ethnicity
  • Gender
  • Age
  • Sexual orientation
  • Geographic location
  • Education level
  • Socioeconomic status
  • Health status

A typical example of diversity and inclusion in clinical trials is the testing of a drug to see how it works and how safe it is across a range of the target population. Now, different people react in different ways to the same medicine. When there is sufficiently diverse patient recruitment in clinical trials, it helps ensure the drug is evaluated in patients from various backgrounds and with different characteristics.

Implementing strategies that promote diverse enrollment in clinical trials also reduces the underrepresentation of any particular group of participants. This enhances the ability to collect data about the efficacy and safety of the trial drug. The subject population should be diverse in many factors, including gender diversity and socioeconomic backgrounds. This helps researchers understand the drug’s effectiveness for different cross-sections of society.

The key here is to involve relevant participants in the research – those that may be affected by the condition being studied and could potentially benefit from the results. If the study population is narrow and homogenous, certain populations will not have contributed data. It is important to understand how some diseases may disproportionately impact certain groups and include them in the research. This can help build trust, awareness, and acceptance of the drug.

Why is diversity important in clinical trials?

The advantages of clinical trial diversity are multifold. Diversity allows new drugs to be tested and introduced in markets for medical professionals to recommend them to people with individual health requirements or requirements that differ from person to person.

Diversity in clinical trials patient recruitment contributes to ensuring research equity and building trust and transparency in clinical research.​ It allows for the generalizability of clinical trial results and improved scientific knowledge of drugs tested on a diverse patient population.

Furthermore, delivering a significant positive social impact is one of the most important ethical reasons for diversity and inclusion in clinical trials. It helps reduce social inequality and social disparities in health and healthcare.

The FDA issued a final guidance document in November 2020 for the medical industry on enhancing the diversity of clinical trial populations.

Post the pandemic, it is a good time now to consider how clinical trials can be made more diverse to contribute to health equity and patient outcomes effectively.

How do we improve diversity in clinical trials?

Clinical Sites

To enable diversity in clinical trial patient recruitment, clinical sites can thoroughly inspect their medical record systems before the start of the study. This helps screen and identify early potential participants to ensure diverse patient recruitment for clinical trials. Clinical sites can also create a custom patient recruitment plan to include more diverse participants from varied demographic and other backgrounds.

Investing in the clinical site workforce, which includes study coordinators and research nurses, is vital to keeping diversity efforts alive in clinical trials. This workforce does most of the close communication activities and relationship building with research participants. Hence, reducing the employee turnover rate at clinical sites is incredibly important. Additionally, providing clinical research resources and investing in proper training to educate and develop the workforce is always beneficial.

Clinical sites can also have patient and family advisory councils to review clinical trials before or in tandem with an Institutional Review Board (IRB) submission. In addition, proactive participant recruitment strategies for underrepresented populations can be created to reach previously underrepresented communities.


Sponsors can also play a pivotal role in improving diversity in clinical trials. They can set industry standards, design broader study endpoints, and expand eligibility criteria for participation to foster inclusiveness in clinical trials. Furthermore, they can strengthen diverse patient recruitment and retention by establishing collaborative industry groups to implement supporting guidelines and frameworks.

Sponsors can also contribute to reimagining research practices to achieve research equity. This can be done by:

  • Creating an inclusive research design
  • Developing research questions by keeping participants in mind
  • Studying what participants are most interested in
  • Giving fair market value compensation to participants for their partnership
  • Developing partnership programs with clinical sites and Federally Qualified Health Centers (FQHC) to financially support their educational and outreach efforts for diverse patient recruitment
  • Developing programs that allow hospitals, clinical sites, and community centers to submit Request for Proposals (RFP) for receiving funding and collaborating on initiatives that improve health and research equity

Building Trust with Patients for Clinical Trials Diversity

Improving cultural competency is one of the best ways to increase trust with study participants while fostering diversity in clinical trials. It is important to understand where participants come from and their specific beliefs, concerns, communities, languages, and practices. A clinical trial workforce with such understanding can better connect with diverse patient populations.

Clinical sites and sponsors can also invest in research staff training or embed this training in medical school or public health curricula to build cultural competency.

Accountability and consent are other crucial aspects of building trust and transparency with participants for stronger patient partnerships and diversity in clinical trials.

Patient Empowerment for Diversity in Clinical Trials

It’s difficult to imagine reaching true health equity and clinical trial diversity without empowering study participants. For clinical sites and sponsors, staying consistent with patient empowerment efforts and providing sustainable resources to ensure diversity in clinical trials is essential. Patient representation within institutional systems can help to listen to concerns and answer queries from diverse patient populations.

Furthermore, clinical sites can ensure they incorporate plain language health literacy principles as part of patient empowerment to support inclusion and diversity in clinical trials. This includes the grouping of communication factors that can affect a patient’s health. A patient’s health literacy can change over time and may not correlate with their educational or literacy level. Therefore, it makes sense to make it a standard practice to use plain language in clinical trials.

Code of Ethics for Human Subjects Research to Support Diversity

Following recommended ethics is paramount to maintaining public trust and supporting diversity in clinical trials. Human dignity should be at the core of research and clinical trial ethics, especially when dealing with underrepresented or vulnerable patient populations.

According to the Belmont Report, the three fundamental principles particularly relevant to the ethics of research involving human subjects are:

  • Respect of persons
  • Beneficence
  • Justice

Not to forget, upholding the following core values is also critical to enabling clinical trials diversity:

  • Trust
  • Honesty
  • Ethics
  • Integrity
  • Quality
  • Statement
  • Patience

Simply put, sustaining diversity in clinical trials is good science and good ethics.

If you would like to learn more about ways to improve diversity and equity in clinical trials, consider CITI Program’s insightful webinar Research Equity and the Part We Play.

The webinar features Nicole A. Fisher, BS, GSK Director and Clinical misTrials Podcast Host. Nicole is a bioethics and human subjects research professional experienced in implementing community and patient partnerships within pharma to improve health equity and public trust.

The webinar explores strategies to address the inequities within research practices to ensure the ethical inclusion of subjects in clinical trials. These include incorporating research equity by design, enlisting ethical recruitment and retainment practices, building trust and transparency, and seeking subject empowerment.