Methods
We reviewed all systematic reviews and meta-analyses in Cochrane Database of Systematic Reviews from January 2016 through May 2021 (n=3,323). We identified 414(207x2) and 384 (192x2) pairs of original and updated Cochrane reviews that assessed CoE and pooled treatment effect estimates. We appraised CoE using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method. We assessed the difference in effect sizes between the original versus updated reviews as a function of change in CoE, which we report as a ratio of odds ratio (ROR). We compared ROR generated in the studies that changed CoE from very low/low (VL/L) to moderate/high (M/H) vs. MH/HVL/L. We also assessed the heterogeneity and inconsistency (using the tau andI 2 statistic), the change in precision of effect estimates (by calculating the ratio of standard errors) (seR), and the absolute deviation in estimates of treatment effects (aROR).