GRADE Guidance 34: update on rating imprecision using a minimally contextualized approach

Area of Science:

• Health Research Methodology
• Evidence-Based Practice

Background:

• The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system requires clear criteria for rating down evidence quality due to imprecision.
• Previous GRADE guidance from 2011 addressed imprecision but required further refinement for practical application.

Approach:

• This guidance was developed through iterative discussions and presentations within the GRADE Working Group.
• It builds upon the 2011 GRADE guidance on imprecision rating.

Key Points:

• GRADE recommends aligning imprecision criteria for systematic reviews and guidelines using a confidence interval (CI) approach.
• When a CI appreciably crosses thresholds of interest, consider rating down two or three levels for imprecision.
• If the sample size is substantially smaller than the optimal information size (OIS), rating down more than one level for imprecision is warranted.

Conclusions:

• Updated GRADE guidance provides a minimally contextualized approach for rating down evidence due to imprecision.
• The guidance emphasizes circumstances where rating down two or three levels for imprecision should be seriously considered.