What to Do If Your PROSPERO Registration Gets Rejected

A PROSPERO submission returned with a request for clarification is a genuinely normal part of the registration process, not a rejection of your review or your competence as a researcher. Understanding the specific, recurring reasons this happens makes the revision process much faster the second time around.

What PROSPERO's review actually checks

PROSPERO's administrative review confirms your submission is complete and appropriately scoped for the registry -- it is not peer review of your methodology's quality, and a successful registration does not mean your methods have been independently validated. Understanding this distinction matters, since the specific things that get flagged are almost always about completeness and clarity, not about whether your planned approach is good research.

Vague eligibility criteria

This is the single most common reason a submission gets returned. A statement like "randomized controlled trials will be included" without further specification of population, intervention details, or outcome requirements doesn't give reviewers -- or future readers -- enough to judge what would or wouldn't qualify. The fix is straightforward: expand your eligibility criteria fields with the same specificity you'd want your own PICO or PICOS framing to have.

Incomplete search strategy description

A search strategy field stating only "PubMed, Embase, and other relevant databases will be searched" without naming a representative search string or explaining your approach to term selection is commonly flagged. Adding your actual planned search terms, or a representative example if the full strategy is still being finalized across multiple databases, typically resolves this.

Missing or unclear risk-of-bias methodology

If your review anticipates including both randomized and non-randomized studies, the risk-of-bias field needs to specify both RoB 2 and ROBINS-I explicitly, matched to the corresponding study designs, rather than a vague statement that "studies will be critically appraised." This specific gap is common enough that it's worth double-checking before you submit, not just when a return prompts you to.

Registration timing concerns

If your registration date appears to postdate other evidence about when your review's screening actually began -- for instance, if other public information suggests work started well before the registration submission -- this can be flagged, since it undermines the core purpose of registration as a pre-specification record. If this happens legitimately (a delayed submission of an already-planned protocol), being transparent about the timeline in your eventual manuscript is the right response rather than trying to obscure it.

Scope mismatches

PROSPERO is specifically for reviews with a health-related outcome. A submission that reads as more general social science or educational research without a clear health dimension may be flagged as out of scope, and in genuine cases, the Open Science Framework is a more appropriate registry.

How to actually respond

Read the specific feedback carefully rather than resubmitting a lightly modified version and hoping it passes -- the feedback usually points to one or two specific fields needing more detail, and addressing those directly, with real specificity, is faster than guessing at a broader revision. Most resubmissions after addressing specific feedback go through without further issues.

Preventing this on your next registration

Before submitting, run through your draft registration against the common gaps above: are your eligibility criteria specific enough that a stranger could apply them consistently? Does your search strategy field include actual search terms, not just database names? Have you specified your risk-of-bias tool by name, matched to your anticipated study designs? Catching these gaps before submission, rather than after a return, saves a full review cycle and gets your protocol timestamped and public sooner -- which is, after all, the entire point of registering early.

Response time expectations

PROSPERO's administrative review typically completes within a few working days, and a returned submission requiring revision usually goes through a similarly quick second review once resubmitted with the requested detail. This means a return, while mildly frustrating, rarely adds more than a week or so to your overall timeline if you respond to the specific feedback promptly rather than letting the resubmission sit unaddressed.

Getting a second pair of eyes before you submit

Given how consistently the same handful of gaps -- vague eligibility criteria, an underspecified search strategy, an unclear risk-of-bias plan -- account for most returns, having a colleague or methodology consultant review your draft registration against these specific points before you submit is a genuinely effective way to reduce your chance of a return altogether. This kind of pre-submission check costs very little time relative to a full review cycle, and catching an obvious gap before submission is always faster than catching it after.

Amendments are normal, even after successful registration

A successful initial registration doesn't mean your protocol is locked in stone -- PROSPERO explicitly supports amendments as your review progresses, and using this feature to log a genuine, justified change in your methodology as it happens is far better practice than either rigidly refusing to adapt when a genuine need arises, or quietly changing course without documenting it. A visible, dated amendment history is a feature of good registration practice, not a mark against your review's rigor. Reviewers and readers who check your registration against your final manuscript are generally looking for undisclosed deviations specifically, not the presence of any deviation at all -- a logged, explained amendment reads as careful methodology, not as a flaw. Researchers sometimes avoid amending a registered protocol out of a mistaken worry that any change will be read as a weakness, when in practice a transparent, well-justified amendment is exactly the kind of visible methodological honesty that strengthens rather than undermines confidence in a review. Framing amendments this way, both to yourself and in how you eventually describe your process in your manuscript, helps normalize what should be normal: a living protocol that adapts transparently as genuine circumstances require it to. That transparency is, ultimately, the entire point of registering a protocol publicly in the first place, not an obstacle to working around. Keeping that purpose in view makes the amendment process feel far less like an admission and far more like the system working as intended.