Improving GRADE evidence tables part 3: Detailed guidance for explanatory footnotes supports creating and understanding GRADE certainty in the evidence judgments

Background The Grading of Recommendations Assessment, Development and Evaluation (GRADE) is widely used and reliable and accurate for assessing the certainty in the body of health evidence. The GRADE working group has provided detailed guidance for assessing the certainty in the body of evidence in systematic reviews and health technology assessments (HTAs) and how to grade the strength of health recommendations. However, there is limited advice regarding how to maximize transparency of these judgments, in particular through explanatory footnotes or explanations in Summary of Findings tables and Evidence Profiles (GRADE evidence tables). Methods We conducted this study to define the essential attributes of useful explanations and to develop specific guidance for explanations associated with GRADE evidence tables. We used a sample of explanations according to their complexity, type of judgment involved, and appropriateness from a database of published GRADE evidence tables in Cochrane reviews and World Health Organization guidelines. We used an iterative process and group consensus to determine the attributes and develop guidance. Results Explanations in GRADE evidence tables should be concise, informative, relevant, easy to understand, and accurate. We provide general and domain-specific guidance to assist authors with achieving these desirable attributes in their explanations associated with GRADE evidence tables. Conclusions Adhering to the general and GRADE domain-specific guidance should improve the quality of explanations associated with GRADE evidence tables, assist authors of systematic reviews, HTA reports, or guidelines with information that they can use in other parts of their evidence synthesis. This guidance will also support editorial evaluation of evidence syntheses using GRADE and provide a minimum quality standard of judgments across tables.