The GRADE Working Group clarifies the construct of certainty of evidence

Monica Hultcrantz, David Rind, Elie A. Akl, Shaun Treweek, Reem A. Mustafa, Alfonso Iorio, Brian S. Alper, Joerg J. Meerpohl, M. Hassan Murad, Mohammed T. Ansari, Srinivasa Vittal Katikireddi, Pernilla Östlund, Sofia Tranæus, Robin Christensen, Gerald Gartlehner, Jan Brozek, Ariel Izcovich, Holger Schünemann, Gordon Guyatt

Research output: Contribution to journalArticlepeer-review

137 Scopus citations


Objective To clarify the grading of recommendations assessment, development and evaluation (GRADE) definition of certainty of evidence and suggest possible approaches to rating certainty of the evidence for systematic reviews, health technology assessments, and guidelines. Study Design and Setting This work was carried out by a project group within the GRADE Working Group, through brainstorming and iterative refinement of ideas, using input from workshops, presentations, and discussions at GRADE Working Group meetings to produce this document, which constitutes official GRADE guidance. Results Certainty of evidence is best considered as the certainty that a true effect lies on one side of a specified threshold or within a chosen range. We define possible approaches for choosing threshold or range. For guidelines, what we call a fully contextualized approach requires simultaneously considering all critical outcomes and their relative value. Less-contextualized approaches, more appropriate for systematic reviews and health technology assessments, include using specified ranges of magnitude of effect, for example, ranges of what we might consider no effect, trivial, small, moderate, or large effects. Conclusion It is desirable for systematic review authors, guideline panelists, and health technology assessors to specify the threshold or ranges they are using when rating the certainty in evidence.

Original languageEnglish (US)
Pages (from-to)4-13
Number of pages10
JournalJournal of Clinical Epidemiology
StatePublished - Jul 2017


  • Certainty of evidence
  • Guidelines
  • Health technology assessment
  • Systematic reviews
  • Thresholds

ASJC Scopus subject areas

  • Epidemiology


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