How to Allocate Candidates When Studies Compete for the Same Patients

Most sites don't fail at recruitment because they can't find patients. They fail because eight studies are open, three of them compete for the same person, and nobody owns the decision about who goes where. Running concurrent recruitment well is less about outreach volume and more about allocation discipline.

Map overlap before you accept the study

The moment you sign a confidentiality disclosure agreement, build a simple overlap grid. Rows are your open and pending protocols. Columns are the attributes that actually create competition:

• Primary indication and severity band
• Washout and prior-exposure exclusions
• Concurrent-trial participation rules
• Visit burden and travel requirements
• Referral source you'd lean on

Two diabetes studies aren't necessarily in conflict if one wants drug-naive patients and the other wants triple-therapy failures. Two insomnia studies pulling from the same community ad spend absolutely are. The grid tells you which studies can run in parallel on autopilot and which need a referee.

Decide the triage rules once, in advance

When a candidate fits two protocols, coordinators shouldn't improvise. Write the rules down and post them where screening happens. Reasonable tiebreakers, roughly in order:

1. Enrollment deadline risk. The study closing first, or already behind its sponsor-agreed curve, gets first look.
2. Rarity of the phenotype. If this patient is hard to replace for Study A and easy for Study B, assign to A.
3. Participant fit. Visit schedule, procedures, and travel burden against what you know about the person. A worse-fit assignment becomes a screen fail or an early withdrawal.
4. Financial and staffing reality. A study you can't actually run visits for shouldn't be winning candidates.

Participant preference, when you offer it, should be informed rather than a menu dump. Describe both commitments honestly and let them choose.

Give every study a named owner and a visible number

In most site datasets, the studies that stall are the ones where recruitment was "everyone's job." Assign one coordinator as recruitment lead per protocol, even if visit work is shared. Their weekly obligation is a single number: candidates contacted, pre-screens completed, screens scheduled, consents signed.

Then put all of them on one board. A shared view by study makes the stalled column obvious in seconds, which is the real point. Sites commonly discover that one protocol has absorbed most of the outreach attention simply because it was easiest to talk about.

Protect the quiet studies

Every portfolio has a protocol that's slow, unglamorous, and behind. Left alone, it gets nothing. Two tactics work:

• Reserve capacity. Block specific screening slots per study rather than first-come-first-served. If the hard study has Tuesday mornings, Tuesday mornings don't get consumed by the easy one.
• Rotate the database queries. Don't re-mine the same list for your favorite study. Keep a log of which chart-review criteria you've already run so searches cover the whole portfolio.

Review the portfolio weekly, not monthly

A 20-minute standing meeting is enough: each study's number, anything blocking it, and reallocation decisions for the coming week. Decide explicitly when to pause outreach on a study that's nearly enrolled so the spend and staff attention shift elsewhere. That one habit — deliberate reallocation instead of drift — separates sites that finish most of their studies from sites that finish one and apologize for the rest.