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Research Methods & Reporting

The PRISMA 2020 statement: an updated guideline for reporting systematic reviews

BMJ 2021; 372 doi: (Published 29 March 2021) Cite this as: BMJ 2021;372:n71

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PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews

  1. Matthew J Page, senior research fellow1,
  2. Joanne E McKenzie, associate professor1,
  3. Patrick M Bossuyt, professor2,
  4. Isabelle Boutron, professor3,
  5. Tammy C Hoffmann, professor4,
  6. Cynthia D Mulrow, professor5,
  7. Larissa Shamseer, doctoral student6,
  8. Jennifer M Tetzlaff, research product specialist7,
  9. Elie A Akl, professor8,
  10. Sue E Brennan, senior research fellow1,
  11. Roger Chou, professor9,
  12. Julie Glanville, associate director10,
  13. Jeremy M Grimshaw, professor11,
  14. Asbjørn Hróbjartsson, professor12,
  15. Manoj M Lalu, associate scientist and assistant professor13,
  16. Tianjing Li, associate professor14,
  17. Elizabeth W Loder, professor15,
  18. Evan Mayo-Wilson, associate professor16,
  19. Steve McDonald, senior research fellow1,
  20. Luke A McGuinness, research associate17,
  21. Lesley A Stewart, professor and director18,
  22. James Thomas, professor19,
  23. Andrea C Tricco, scientist and associate professor20,
  24. Vivian A Welch, associate professor21,
  25. Penny Whiting, associate professor17,
  26. David Moher, director and professor22
  1. 1School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
  2. 2Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, Netherlands
  3. 3Université de Paris, Centre of Epidemiology and Statistics (CRESS), Inserm, F 75004 Paris, France
  4. 4Institute for Evidence-Based Healthcare, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Australia
  5. 5University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA; Annals of Internal Medicine
  6. 6Knowledge Translation Program, Li Ka Shing Knowledge Institute, Toronto, Canada; School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, Canada
  7. 7Evidence Partners, Ottawa, Canada
  8. 8Clinical Research Institute, American University of Beirut, Beirut, Lebanon; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
  9. 9Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Science University, Portland, Oregon, USA
  10. 10York Health Economics Consortium (YHEC Ltd), University of York, York, UK
  11. 11Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada; School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada; Department of Medicine, University of Ottawa, Ottawa, Canada
  12. 12Centre for Evidence-Based Medicine Odense (CEBMO) and Cochrane Denmark, Department of Clinical Research, University of Southern Denmark, Odense, Denmark; Open Patient data Exploratory Network (OPEN), Odense University Hospital, Odense, Denmark
  13. 13Department of Anesthesiology and Pain Medicine, The Ottawa Hospital, Ottawa, Canada; Clinical Epidemiology Program, Blueprint Translational Research Group, Ottawa Hospital Research Institute, Ottawa, Canada; Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
  14. 14Department of Ophthalmology, School of Medicine, University of Colorado Denver, Denver, Colorado, United States; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
  15. 15Division of Headache, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Head of Research, The BMJ, London, UK
  16. 16Department of Epidemiology and Biostatistics, Indiana University School of Public Health-Bloomington, Bloomington, Indiana, USA
  17. 17Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
  18. 18Centre for Reviews and Dissemination, University of York, York, UK
  19. 19EPPI-Centre, UCL Social Research Institute, University College London, London, UK
  20. 20Li Ka Shing Knowledge Institute of St. Michael's Hospital, Unity Health Toronto, Toronto, Canada; Epidemiology Division of the Dalla Lana School of Public Health and the Institute of Health Management, Policy, and Evaluation, University of Toronto, Toronto, Canada; Queen's Collaboration for Health Care Quality Joanna Briggs Institute Centre of Excellence, Queen's University, Kingston, Canada
  21. 21Methods Centre, Bruyère Research Institute, Ottawa, Ontario, Canada; School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, Canada
  22. 22Centre for Journalology, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada; School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, Canada
  1. Correspondence to: M J Page{at}
  • Accepted 4 January 2021

The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement, published in 2009, was designed to help systematic reviewers transparently report why the review was done, what the authors did, and what they found. Over the past decade, advances in systematic review methodology and terminology have necessitated an update to the guideline. The PRISMA 2020 statement replaces the 2009 statement and includes new reporting guidance that reflects advances in methods to identify, select, appraise, and synthesise studies. The structure and presentation of the items have been modified to facilitate implementation. In this article, we present the PRISMA 2020 27-item checklist, an expanded checklist that details reporting recommendations for each item, the PRISMA 2020 abstract checklist, and the revised flow diagrams for original and updated reviews.

Systematic reviews serve many critical roles. They can provide syntheses of the state of knowledge in a field, from which future research priorities can be identified; they can address questions that otherwise could not be answered by individual studies; they can identify problems in primary research that should be rectified in future studies; and they can generate or evaluate theories about how or why phenomena occur. Systematic reviews therefore generate various types of knowledge for different users of reviews (such as patients, healthcare providers, researchers, and policy makers).12 To ensure a systematic review is valuable to users, authors should prepare a transparent, complete, and accurate account of why the review was done, what they did (such as how studies were identified and selected) and what they found (such as characteristics of contributing studies and results of meta-analyses). Up-to-date reporting guidance facilitates authors achieving this.3

The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement published in 2009 (hereafter referred to as PRISMA 2009)45678910 …

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