Brief · Use case · Clinical Operations
Enrollment Stall Diagnosis.
LiveDiagnosisFind out why trial enrollment is behind target: eligibility, site activation, competing trials or patient burden, and what would confirm which.
Enrollment Stall Diagnosis is a ready-made use case for Clinical Operations. It ships under the Diagnosis template.
For clinical operations leads with a trial behind plan. You get the stall stated in measurable terms, several explanations tested against the evidence, the likely cause with a confidence level and the checks that would settle it. Figures are cited to the data you supply or marked as gaps.
Add it to your library to reuse from New → From template. Edit the saved copy in your library on the service form.
The decision
Why has a Phase 3 trial in moderate-to-severe atopic dermatitis reached only 40 percent of its enrollment target after six months: eligibility criteria, site activation, competing trials or patient burden?
The explanations weighed
The diagnosis restates the stall in measurable terms first: patients screened, screen-failed and randomized, by site and by month, against the plan.
| Explanation | What it would look like | What would confirm or refute it |
|---|---|---|
| Eligibility criteria | The criteria exclude more patients than planned. FDA’s guidance on enhancing the diversity of trial populations covers how eligibility criteria, enrollment practices and trial designs can be broadened.1 | Confirmed by a screen-failure log showing the same criterion removing many candidates. Refuted if screen-failure is low. |
| Site activation | Sites opened later or enrolled slower than the plan assumed. | Confirmed by activation dates and enrollment per active site. Refuted if the active sites are enrolling at the planned rate. |
| Competing trials | Other trials in the same condition draw the same patients and the same sites. Public registers show which trials are recruiting.3 | Confirmed by overlapping trials at the same sites in the registers. Refuted if the sites have no competing trial. |
| Patient burden | The visit schedule or procedures deter patients. FDA’s guidance on decentralized elements describes ways to carry out trial activities away from traditional sites.2 | Confirmed by drop-out before randomization tied to visit load. Refuted if refusal reasons are unrelated to burden. |
What the diagnosis does
Enrollment as a funnel. The diagnosis breaks the 40 percent into screened, screen-failed, consented and randomized, by site and by month, and says where in the funnel the shortfall opens. A stall at screening points to a different cause than a stall at consent.
Eligibility, with a regulator’s view. FDA’s November 2020 guidance sets out how eligibility criteria, enrollment practices and trial designs can be broadened to include more patients. The diagnosis checks whether a criterion in this protocol is narrower than the disease needs, without proposing an amendment.1
Competition, checked in the registers. The diagnosis searches ClinicalTrials.gov and the EU system for trials recruiting in the same condition and at the same sites, and reports what it found and the date.3
Burden, with the decentralized options. FDA finalized its guidance on decentralized elements in September 2024. The diagnosis says whether the visit schedule could be shortened by such elements, and that is a finding and not a recommendation.2
Recommended length
Comprehensive
The question asks you to weigh at least three explanations. The matrix that does that, and the Pareto view of where the effect sits, are in the Comprehensive length. Standard names a cause without the side-by-side.
You can pick another length on the form. The other two stay available.
Assumptions the diagnosis checks
The diagnosis states the assumptions its likely cause rests on and sets what would break each one. Examples for this problem:
- The target and the timeline in the plan were set from realistic site and patient estimates.
- The screening log is complete and its reasons are recorded consistently.
- The registers show the competing trials that matter.
Standards, guidance and sources
Regulators
Registers
- ClinicalTrials.gov and the EU Clinical Trials Information System, searched on a stated date.3
The decision practice behind the memo itself is on the template page.
What gets flagged
Any explanation the screening log cannot separate, any site whose data are missing, and any competing trial found in only one register.
What arrives
- The problem as stated
- What is actually happening
- Competing explanations
- The likely cause
- What would confirm it
- Where the effect concentrates
- What to rule out
What it will not do
It does not decide what to do about the cause. A Decision Memo takes the diagnosis as its starting point.
It does not propose a protocol amendment or a change of sites.
It does not prove the cause. It names the most likely cause, says how sure it is, and says what would show it to be wrong.
It does not assign blame. It looks for contributing causes in the system, in the way a blameless postmortem does.
It does not act. Deciding what to do about the cause is a different question; a Decision Memo is the template for it.
References
- [1] U.S. Food and Drug Administration. Enhancing the Diversity of Clinical Trial Populations — Eligibility Criteria, Enrollment Practices, and Trial Designs. Final guidance, November 2020. Title and date as given in FDA presentations and announcements; the guidance text was not read.
- [2] U.S. Food and Drug Administration. Conducting Clinical Trials With Decentralized Elements. Final guidance, September 2024. Docket FDA-2022-D-2870. Status and definition as given in FDA’s announcement and search excerpts; the guidance text was not read in full.
- [3] U.S. National Library of Medicine, ClinicalTrials.gov; European Medicines Agency, Clinical Trials Information System (CTIS) public site. Search on a stated date; results change.
Links checked 9 October 2026
These are the sources the template drew on. None of their authors or issuers has reviewed it.
About the Brief service
A Brief is a written answer from one specialist, at the depth you asked for. It arrives with its sources, and it closes by saying plainly what would change the conclusion. Nothing is hidden behind a summary, and anything the expert could not source is marked as a gap rather than filled in.
To edit a saved template, open New → Brief → From template, or the library rail on the service form.