Ask a recruitment team how to improve diversity in a clinical trial, and the obvious answer is to reach more people.
More outreach to identify more candidates, with better follow-through. That should bring in more diverse participants, but only if those reached qualify under the protocol.
Eligibility conditions limit who recruitment can bring into the trial. Even someone identified through diversity outreach may be exactly who the team hoped to reach but remain ineligible. Recruitment can identify that person and assess eligibility, documenting why progression stops. It can’t recruit someone who does not meet the protocol’s eligibility conditions.
The distinction gets lost when the final result is treated as a verdict on recruitment. A trial may recruit fewer diverse participants because eligible prospects were not successfully brought in. [1] Eligibility rules may also exclude people the team reaches who could contribute to diversity, limiting the diversity of recruits.
Only the first points toward a possible problem with recruitment execution.
Reaching a candidate is not the same as being able to recruit them
When someone doesn’t advance, the reason matters.
A candidate who meets the eligibility conditions but never joins the recruited population raises a question about recruitment effectiveness among people permitted to participate. For a candidate assessed as ineligible, better outreach and more diligent follow-through can’t change the eligibility determination.
That doesn’t make the work of finding and assessing candidates pointless.
Reaching more people can reveal which candidates identified through diversity efforts could not advance because of eligibility conditions. It gives the team a clearer account of who was assessed and why some could not move forward.
That visibility doesn’t show that more outreach would have produced more eligible recruits, and identifying more excluded candidates doesn’t change the protocol’s conditions.
The MyTACTIC oncology trial shows how that distinction can matter in practice. Despite efforts to broaden participation through community clinics and patient support, five screening failures among racial and ethnic minority patients were attributed to glucose or HbA1c requirements. In one treatment arm, those requirements could not be relaxed because of the risk of hyperglycemia. Improving access to the trial could not remove an eligibility restriction that remained necessary for patient safety. [2]
You can get better at finding people without increasing the number who qualify.
The population behind the recruitment number
A reported diversity recruitment shortfall may seem clear until you examine who the measure includes.
Recruitment identifies people who may not qualify for the trial. Measuring performance against everyone identified can therefore mistake eligibility exclusions for recruitment failures. Looking only at candidates who qualify answers a different, more precise question: how effectively did recruitment bring eligible prospects into the recruited population?
That doesn’t mean eligibility exclusions can be ignored. The diversity of recruited participants depends on both the population allowed to participate and recruitment effectiveness within that population. [3]
Even excellent recruitment among eligible prospects doesn’t tell you whether the eligible population is broad. And evidence that the protocol excludes some candidates doesn’t tell you whether recruitment is doing a good job reaching those who qualify.
The evidence needs to reflect both conditions. Eligibility determinations show who was prevented from progressing by the protocol; recruitment results among eligible candidates show what was delivered within those rules. The composition of the eligible population helps explain how diverse the recruited population could be.
Without that separation, the recruitment figure may be accurate while the judgment about responsibility is not.
Better recruitment doesn’t rewrite eligibility rules
Now suppose the recruitment numbers improve.
More eligible prospects enter the recruited population because the team reaches them more effectively or follows through more successfully. That’s a genuine improvement in delivery, demonstrating what recruitment can accomplish inside the existing eligibility conditions.
It says nothing about whether a person previously excluded can now take part.
Changing the protocol’s eligibility conditions may expand the eligible population without improving recruitment effectiveness. Improving recruitment among eligible prospects and changing who qualifies under the protocol require separate evidence.
A better result in either area can’t be used as proof that the other has improved.
Recruitment should answer for what it can control
This is where a performance measure becomes an accountability problem.
If a shortfall in diversity is assigned entirely to recruitment, the team may be held responsible for the exclusions it encounters rather than the eligibility decisions that produce them. A final recruitment number can’t establish who caused the limitation.
You need to know who was excluded by eligibility conditions and what recruitment achieved among those who qualified. Documenting exclusions explains why candidates could not advance, but it can’t expand eligibility or make someone a qualifying recruit, regardless of recruitment efforts.
A complete record of eligibility exclusions makes recruitment performance easier to judge without changing who can enter the trial under the protocol.
Recruitment is accountable for reaching and recruiting eligible people, not making ineligible people eligible.
Sources:
[1] American Society of Clinical Oncology (JCO Oncology Practice). Ineligible, Unaware, or Uninterested? Associations Between Underrepresented Patient Populations and Retention in the Pathway to Cancer Clinical Trial Enrollment. Peer-reviewed retrospective study, published online September 30, 2022. Peer-reviewed research article
[2] Taylor & Francis (Future Oncology). Impact of community recruitment and inclusion initiatives on enrollment in the biomarker-driven MyTACTIC trial. Peer-reviewed retrospective implementation analysis, published online December 15, 2025. Full-text research article
[3] BMC Cancer (Springer Nature). Eligibility criteria and study phase limit racial/ethnic enrollment in oncology clinical trials. Peer-reviewed observational research, April 17, 2026. Peer-reviewed research article