Inclusion/Exclusion Criteria Builder

A PICOS criteria generator operationalises the structured framework that the Cochrane Handbook (Higgins et al., 2023, Chapter 3) identifies as the cornerstone of every systematic review protocol. PICOS decomposes the review question into five elements (Population, Intervention, Comparator, Outcome, and Study design) so that two independent screeners can apply the same decision rules with minimal ambiguity. Richardson et al. (1995) originally proposed the PICO framework for clinical question formulation; the subsequent addition of the Study-design element reflects the reality that restricting a review to randomised controlled trials, for instance, demands an explicit a priori declaration. Before defining detailed criteria, researchers should first articulate a focused research question using our PICO framework builder, which structures the question into its constituent elements and ensures that every PICOS dimension is addressed before screening begins. For qualitative or mixed-methods evidence syntheses, the SPIDER framework (Cooke et al., 2012) replaces Intervention and Comparator with Phenomenon of Interest, Design, Evaluation, and Research type, offering a more natural fit when the question concerns lived experiences rather than treatment effects. For diagnostic accuracy reviews, the QUADAS-2 framework (Whiting et al., 2011) provides a complementary set of eligibility considerations covering patient selection, index test, reference standard, and flow and timing.

An inclusion exclusion criteria tool must enforce the pre-specification principle that PRISMA 2020 (Page et al., 2021) codifies in its checklist: eligibility criteria should be defined and registered before the literature search is executed, not modified retrospectively in response to search results. Post-hoc changes introduce selection bias and undermine the transparency that distinguishes a systematic review from a narrative one. The JBI Manual (Aromataris & Munn, 2020) recommends pilot-testing criteria on a random sample of 50 abstracts, measuring inter-rater agreement, and refining any ambiguous wording before full screening commences. A Cohen's kappa of at least 0.60 during pilot screening is generally considered the minimum acceptable inter-rater agreement threshold before proceeding to full screening. Screening software such as Covidence and EPPI-Reviewer operationalises these criteria by allowing reviewers to apply structured eligibility rules at scale, with built-in conflict resolution and agreement reporting. Our free abstract screening tool does the same in your browser, ranking records against these criteria and tallying structured exclusion reasons. Once criteria are finalised, translating them into Boolean search strings is the next step; our search strategy builder converts PICOS elements into database-specific queries for PubMed, Embase, and the Cochrane Central Register, keeping the search deliberately broader than the eligibility criteria so that borderline studies are captured during screening rather than missed during retrieval.

Systematic review eligibility criteria feed directly into protocol registration, PRISMA flow documentation, and data extraction planning. The Cochrane Handbook (Higgins et al., 2023, Chapter 3) states that every protocol submitted to PROSPERO must enumerate inclusion and exclusion rules for each PICOS element in sufficient detail that the review could be replicated by an independent team. Our PROSPERO registration formatter accepts the structured output from this criteria builder and maps it to the required registration fields, reducing transcription errors and ensuring completeness. The criteria also determine the denominators in the PRISMA flow diagram, specifically how many records were excluded at title/abstract screening versus full-text review, which our PRISMA flow generator renders as a publication-ready figure with exclusion reasons linked back to specific PICOS elements. For living systematic reviews, eligibility criteria must also include temporal updating rules that define how frequently new evidence is incorporated and what triggers a re-screening cycle.

Methodological rigour requires that eligibility decisions are documented at the study level, not merely summarised in aggregate. PRISMA 2020 (Page et al., 2021) now mandates a list of studies excluded at the full-text stage together with the reason for each exclusion, a requirement that underscores the need for unambiguous, pre-specified criteria. The JBI Manual (Aromataris & Munn, 2020) extends this guidance to scoping and qualitative reviews, adapting the PICOS framework into PCC (Population, Concept, Context) for non-interventional questions. Regardless of the framework chosen, the eligibility criteria ultimately shape the data that will be extracted; our data extraction template builder aligns its fields with the PICOS elements defined here, creating a seamless workflow from question formulation through screening to quantitative synthesis. By enforcing structure, transparency, and pre-registration, this tool helps review teams meet the methodological standards that Cochrane, JBI, and PRISMA 2020 set for trustworthy evidence synthesis.