title: Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation.
abstract: Protocols of systematic reviews and meta-analyses allow for planning and documentation of review methods, act as a guard against arbitrary decision making during review conduct, enable readers to assess for the presence of selective reporting against completed reviews, and, when made publicly available, reduce duplication of efforts and potentially prompt collaboration. Evidence documenting the existence of selective reporting and excessive duplication of reviews on the same or similar topics is accumulating and many calls have been made in support of the documentation and public availability of review protocols. Several efforts have emerged in recent years to rectify these problems, including development of an international register for prospective reviews (PROSPERO) and launch of the first open access journal dedicated to the exclusive publication of systematic review products, including protocols (BioMed Central's Systematic Reviews). Furthering these efforts and building on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, an international group of experts has created a guideline to improve the transparency, accuracy, completeness, and frequency of documented systematic review and meta-analysis protocols--PRISMA-P (for protocols) 2015. The PRISMA-P checklist contains 17 items considered to be essential and minimum components of a systematic review or meta-analysis protocol.This PRISMA-P 2015 Explanation and Elaboration paper provides readers with a full understanding of and evidence about the necessity of each item as well as a model example from an existing published protocol. This paper should be read together with the PRISMA-P 2015 statement. Systematic review authors and assessors are strongly encouraged to make use of PRISMA-P when drafting and appraising review protocols.
authors.affiliation: Ottawa Hospital Research Institute and University of Ottawa, Canada lshamseer@ohri.ca.
authors.forename: Larissa
authors.initials: L
authors.lastname: Shamseer
authors.affiliation: Ottawa Hospital Research Institute and University of Ottawa, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Moher
authors.affiliation: Queen's University Belfast, Ireland.
authors.forename: Mike
authors.initials: M
authors.lastname: Clarke
authors.affiliation: National Health and Medical Research Council, Australia.
authors.forename: Davina
authors.initials: D
authors.lastname: Ghersi
authors.affiliation: University of Modena, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Liberati
authors.affiliation: London School of Hygiene and Tropical Medicine, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Petticrew
authors.affiliation: Southern California Evidence-based Practice Center, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Shekelle
authors.affiliation: Centre for Reviews and Dissemination, University of York, UK.
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Stewart
mesh_terms: D022126:Access to Information; D019983:Guideline Adherence; D015201:Meta-Analysis as Topic; D011643:Publishing / Q000458:organization & administration / Q000592:standards; D011786:Quality Control; D012107:Research Design / Q000592:standards*; D058028:Research Report / Q000592:standards*; D000078202:Systematic Reviews as Topic