Abstract
Objective
To establish guidance on grading strength of evidence for the Evidence-based Practice
Center (EPC) program of the U.S. Agency for Healthcare Research and Quality.
Study Design and Setting
Authors reviewed authoritative systems for grading strength of evidence, identified
domains and methods that should be considered when grading bodies of evidence in systematic
reviews, considered public comments on an earlier draft, and discussed the approach
with representatives of the Grading of Recommendations Assessment, Development, and
Evaluation (GRADE) working group.
Results
The EPC approach is conceptually similar to the GRADE system of evidence rating; it
requires assessment of four domains: risk of bias, consistency, directness, and precision.
Additional domains to be used when appropriate include dose–response association,
presence of confounders that would diminish an observed effect, strength of association,
and publication bias. Strength of evidence receives a single grade: high, moderate,
low, or insufficient. We give definitions, examples, mechanisms for scoring domains,
and an approach for assigning strength of evidence.
Conclusion
EPCs should grade strength of evidence separately for each major outcome and, for
comparative effectiveness reviews, all major comparisons. We will collaborate with
the GRADE group to address ongoing challenges in assessing the strength of evidence.
Keywords
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Article info
Publication history
Published online: July 13, 2009
Accepted:
March 11,
2009
Identification
Copyright
© 2010 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
