Using Research Participant Payments to Help Diversify Clinical Research

Clinical Researcher—February 2023 (Volume 37, Issue 1)


Kelly FitzGerald, PhD


The U.S. Food and Drug Administration (FDA) is getting serious about requiring diversity plans for clinical trials, as evidenced by this year’s omnibus spending bill signed by President Biden. Sponsors need to prepare for these new requirements now. A key focus in these diversity plans should be participant payments and reimbursement.

Appropriate payment to research participants is a critical aspect of diversifying clinical research participation.{1} Think of what it takes for you to get to a doctor’s appointment. If you are a parent, you must find childcare. If you work, you need to take time off. If you work in an hourly job or are self-employed, you may not have any paid time off, so you will need to factor in reduced income as well. If you have a disability that affects your mobility, those hurdles are magnified, and you may need to take a caregiver with you. Research studies often involve frequent appointments, and without appropriate compensation, many potential participants will be left out.

IRB Perspective

Institutional review boards (IRBs) are often seen as a barrier to paying participants in clinical research. While that may have been true in the past, thinking on this topic has evolved significantly during the past few years, informed in part by recognition of the importance of research participants as partners rather than as research “subjects.”{2}

IRBs are tasked with ensuring that research recruiting and consenting processes do not exert undue influence on participants, and high payments may be seen by IRB members as unduly influential.{3} Their concern is that payments could incentivize someone to participate in activities they would otherwise choose not to pursue—particularly people with low incomes. However, when an IRB insists on lower payments, participants who have less free time, less available income, or more burdensome lives are less likely to participate, and the study ends up with a participant population that does not match society because only those people who can bear the financial burdens of research participation will enroll.

Current Thinking

The clinical research enterprise now recognizes that payments can incentivize participants without being unduly influential. While there is a perception that IRBs will not approve high payments for participants, that is changing. During the past 24 months, out of approximately 10,000 IRB reviews conducted by WCG IRB, only 13 reviews resulted in the IRB specifically requiring modifications to the participant payment plan (see figure below for the reasons behind these decisions), and no records included a request to decrease the proposed payments to participants.

Should IRBs consider requiring higher payments? The majority of studies reviewed by the IRB do not include any payment to participants other than reimbursement for expenses. Often, even reimbursement is incomplete or capped, requiring participants to pay upfront for ride-shares, taxis, airfare, meals, and hotel stays. IRB discussions rarely focus on this disincentive to participate. Out of the 10,000 records reviewed, not a single one required that payments to participants be increased.

IRB members reflect the values and norms of their communities, and the events of the past few years have led to increased awareness of the importance, both scientifically and ethically, of having diverse representation in clinical trials. However, for improvements in participant diversity to occur, there must be greater support for higher payments to research participants and a reliance on mechanisms other than limiting payments to ensure participants are recruited ethically. This support cannot start at the level of IRB review.


The time has come for sponsors and clinical research organizations to accurately assess the costs to individuals tied to their research participation and provide them with just compensation for their service.{4} These conversations need to be initiated by sponsors during the planning and budgeting process for trials. Ideally, sponsors will work with participant advocacy groups and other community stakeholders to understand the financial challenges faced by a given participant population before developing a budget for recruitment. Appropriate compensation should be considered in the context of the overall goal of improving diversity in clinical trials.


  1. Dutz D, Greenstone M, Hortaçsu A, Lacouture S, Mogstad M, Shaikh A, Torgovitsky A, van Dijk W. 2022. BFI Working Paper NO. 2022-161 – What Drives (Gaps in) Scientific Study Participation? Evidence from a COVID-19 Antibody Survey.
  2. National Academies of Sciences, Engineering, and Medicine. 2022. Improving Representation in Clinical Trials and Research: Building Research Equity for Women and Underrepresented Groups. Washington, D.C.: The National Academies Press.
  3. FDA Payment and Reimbursement to Research Subjects Information Sheet. 2018.
  4. Largent EA, Lynch HF. 2017. Paying Research Participants: The Outsized Influence of “Undue Influence.” IRB 39(4):1–9. PMID: 29038611; PMCID: PMC5640154

Kelly FitzGerald
Kelly FitzGerald, PhD,
is IRB Executive Chair and Vice President, IBC Affairs at WCG IRB.