Extended definition
PROSPERO (International Prospective Register of Systematic Reviews) is the international platform for prospective registration of systematic review protocols, maintained since 2011 by the Centre for Reviews and Dissemination (CRD) at the University of York, with funding from the British National Institute for Health Research (NIHR). Booth et al. (2012, Systematic Reviews) described foundations and operation. Each registration receives a permanent ID and verifiable timestamp; the protocol describes the research question (PICO format), eligibility criteria, search strategy, extraction and synthesis methods, and risk-of-bias appraisal plan — before data extraction begins. Each registration’s full page is public and citable. Coverage spans systematic reviews in health and well-being (including public health, nursing, nutrition, social care), with PROSPERO COVID-19 and specialized pandemic variants. Page and Moher (2017, Systematic Reviews) evaluated the impact of PROSPERO + PRISMA combination on quality and transparency of the systematic review literature.
When it applies
PROSPERO applies to systematic reviews in health and related areas — a definition covering public health, biomedical sciences, epidemiology, nursing, nutrition, social care, mental health. Registration is an effective editorial requirement at Cochrane, BMJ, Lancet, JAMA, PLOS Medicine, and field Q1/Q2 since 2014-2016. It applies in funding proposals that involve systematic review as deliverable: many funders expect or require registration. It applies in doctoral student reviews: PROSPERO offers methodological transparency that protects against unintentional duplication and demonstrates rigor to examination committees. For areas outside health (education, social sciences, engineering), alternatives include OSF Registries, INPLASY, and specific RR registries.
When it does not apply
PROSPERO does not accept reviews outside the health scope — for education, social sciences, engineering, or humanities topics, use OSF Registries or specific platforms. It does not apply to scoping reviews (covered separately in some contexts) nor to standalone meta-analyses not associated with a prior systematic review. It does not apply to reviews already at an advanced stage: registration must be prospective, before data extraction (some retrospective work is clearly marked “ongoing”, but that is editorial gray). It does not replace PRISMA: PROSPERO registers the protocol; PRISMA reports the final study. It does not guarantee quality — registration is methodological transparency, not rigor certification.
Applications by field
— Clinical health: mandatory standard at Cochrane, BMJ, JAMA, NEJM, Lancet, PLOS Medicine. — Public health: reviews on community interventions, health policy, prevention. — Mental health: Cochrane Mental Health Group and similar use PROSPERO registration as standard. — Nursing and nutrition: growing use; JBI Joanna Briggs Institute promotes integration with PROSPERO.
Common pitfalls
The first pitfall is submitting PROSPERO incompletely expecting to “fix it later”: although PROSPERO allows updates with version history, initially vague registrations signal lack of planning and can compromise review credibility. The second is substantially deviating from the registered protocol without documenting and justifying: deviations are legitimate in some cases (e.g., preliminary search revealed unforeseen heterogeneity requiring question adjustment), but must appear in the final report transparently. The third is treating PROSPERO as administrative bureaucracy: a well-done protocol forces methodological clarification that benefits the review as a whole. The fourth is failing to cite the PROSPERO number in the final manuscript: top-tier journals require it; reviewers check protocol-report concordance. The fifth is attempting to register a non-health review on PROSPERO: rejection is virtually automatic; use a platform suited to scope.