Should You Record “Maybe” Studies Separately During Screening?

Is it useful to keep a separate pile of studies you cannot decide yet?

During screening, some records are obvious inclusions for the next stage and others are obvious exclusions. Then there are the awkward ones. The abstract does not report the participants' ages. The intervention might fit your definition, but the description is vague. A mixed sample may contain eligible participants, although you cannot tell whether their results are reported separately.

Instead of forcing an immediate yes-or-no decision, you might be tempted to create a third category: "maybe."

That can be useful, particularly as a temporary workflow device. But it can also become a parking lot for difficult decisions. If dozens or hundreds of studies accumulate there without a clear resolution process, the category has postponed screening rather than improved it.

A temporary “maybe” category can help, but every study still needs a decision

The value of a “maybe” category depends on what you use it for

Study selection ultimately requires a decision

Formal evidence-synthesis guidance generally conceptualizes study selection as determining whether records and reports satisfy predefined eligibility criteria. PRISMA 2020 distinguishes records screened, reports sought for retrieval, reports assessed for eligibility, and studies included in the review. It does not establish "maybe" as a final category of study eligibility.

JBI similarly describes study selection as the application of predefined inclusion criteria at title and abstract and then full-text stages. For systematic reviews, it recommends independent selection by two or more reviewers, with disagreements resolved through discussion or a further reviewer.

A "maybe" label is therefore best understood as an internal screening status. It can tell you that a decision is not yet ready to be finalized. It does not create a third methodological state between eligible and ineligible.

“Maybe” is most useful when it tells you what remains unresolved

Not all uncertain studies are uncertain for the same reason. A useful system records why the decision cannot yet be made.

A bare "maybe" label loses most of this information. "Maybe: population not reported in abstract" is much more actionable than "maybe."

At title and abstract screening, uncertainty usually favors moving the record forward

Early screening is based on incomplete information by design. Titles and abstracts cannot be expected to report every characteristic required for final eligibility.

Cochrane advises that title and abstract screening should generally be over-inclusive because a record that appears potentially relevant can be assessed more carefully from the full report. JBI guidance likewise treats title and abstract screening as an initial stage followed by full-text assessment against the inclusion criteria.

This creates an important practical distinction. You may use "maybe" temporarily while organizing the screening process, but a potentially eligible record should not become stranded simply because the abstract does not answer every eligibility question.

If the problem is specifically that the abstract does not contain enough information to decide, obtaining the full report is usually more informative than debating the abstract indefinitely.

A “maybe” category should not replace retrieval

One failure mode is repeatedly postponing records that could be resolved simply by reading the full text.

If an abstract cannot establish the study design, population, intervention, or another required characteristic, and the record remains plausibly eligible, move it to the appropriate next screening stage. That is one of the purposes of retrieving the full text of a potentially relevant paper.

The "maybe" category is most useful when there is an actual dependency: another reviewer needs to adjudicate the case, a full text has not yet been obtained, an author clarification is pending, or an operational rule needs to be settled.

At full-text screening, “maybe” needs a resolution pathway

Full-text screening changes the situation. You now have substantially more information, and the objective is to establish the final eligible study set.

An unresolved full-text record may still be legitimate. Perhaps a crucial methodological detail is absent, two reports from the same study conflict, or reviewers disagree about whether an intervention satisfies an operational definition.

But indefinite uncertainty is not a screening method. Each unresolved report needs a next action and, eventually, a final decision under the review's eligibility procedures.

The first can improve organization. The second weakens transparency because readers cannot tell how the record affected the evidence base.

Do not let “maybe” become shorthand for “I have not thought about it yet”

A large maybe pile can indicate that the eligibility criteria are too vague, that reviewers have not been calibrated, or that difficult decisions are being deferred.

For example, suppose dozens of records are labeled "maybe intervention." That pattern may reveal that your definition of the eligible intervention is not operational enough to distinguish qualifying from nonqualifying studies.

Instead of reconsidering 40 papers independently, identify the recurring ambiguity and establish a decision rule. The same logic underlies handling borderline studies without making arbitrary decisions.

Separate uncertainty from disagreement

A study can be uncertain because the evidence is incomplete, or because two reviewers disagree despite having the same evidence. These situations require different responses.

If information is missing, obtain more information when feasible. If reviewers disagree about how existing information should be interpreted, use the planned consensus or adjudication procedure.

For systematic reviews, JBI recommends independent study selection by two or more reviewers and resolution of disagreements through discussion or a third reviewer. PRISMA 2020 asks authors to report how many reviewers screened records and reports and whether they worked independently.

A software label such as "conflict" or "maybe" may help organize this process, but the methodological safeguard is the resolution procedure, not the label itself.

Keep the reason attached to the record

If you use a maybe category, record enough information to make the next review efficient. Useful notes are short and specific:

• "Population age unclear; check Table 1."
• "Possible eligible subgroup; results may be pooled."
• "Intervention may meet feedback definition; inspect methods."
• "Reviewer disagreement over prospective versus retrospective design."
• "Related report may contain eligible outcome."

A note such as "check later" merely transfers the same uncertainty to your future self, who will be delighted to receive such excellent methodological correspondence.

Do not report temporary “maybe” records as excluded studies

A temporary status should remain separate from the final reason for exclusion. If a paper is eventually excluded because the population is ineligible, record the population reason. If it ultimately qualifies, include it.

For PRISMA reporting, review authors should report the numbers of records and reports moving through the selection process and cite reports that might appear to meet the inclusion criteria but were excluded, explaining why they were excluded. A temporary internal label does not replace a substantive exclusion reason.

Maintaining clear final reasons also supports keeping track of why studies were excluded without confusing workflow status with methodological justification.

Set a point at which the maybe pile must be resolved

A useful screening workflow has a closure rule. For example, unresolved title and abstract records might automatically proceed to full-text retrieval. Full-text maybes might be reviewed at regular adjudication meetings or resolved before the final study-selection database is locked.

The exact workflow can vary. What matters is that every temporary category has an exit.

Without that exit, "maybe" becomes less a methodological category than a small archive of procrastination.

How a “maybe” record should move toward a final decision

Common mistakes when using a “maybe” category

Use “maybe” as a routing label rather than a destination

If your screening software or spreadsheet allows a third category, it can be useful. The category should answer two questions: why is this record unresolved, and what happens next?

For a team review, agree on these rules before screening scales up. A pilot screening exercise can expose ambiguous criteria and help reviewers develop a shared interpretation before thousands of records are classified.

If screening is conducted by more than one person, the temporary category should also remain distinct from formal reviewer disagreement. The methodological reasons for using more than one reviewer during screening extend beyond simply creating another person to inspect the maybe pile.

Before creating a “maybe” category, make sure it has a purpose

Questions about keeping “maybe” studies during screening

“Maybe” should describe what happens next, not where a study stays

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