Understanding and Usefulness of Effect Size and Certainty of Evidence: A Cross-sectional Survey of Evidence-Based Practice Competencies Among Registered Dietitians

The study examined registered dietitians' understanding of effect size interpretation and certainty of evidence, which are important for informed clinical decision-making. Of 11,050 dietitians who received the survey, 210 participated, with 114 respondents included in the analysis. Results showed that dietitians had similar understanding of relative (27.6%) and absolute (27.5%) estimates, with Risk Difference being best understood (30.7% correct responses) and Number Needed to Treat least understood (24.6%). The usefulness of individual approaches was rated similarly, with highest scores for Relative Risk (mean 4.82 on a 7-point scale). Dietitians rated the usefulness of certainty of evidence favorably (mean 5.07). The study recommends expanding education on interpreting effect sizes and certainty of evidence.