Compelling evidence from meta-epidemiological studies demonstrates overestimation of effects in randomized trials that fail to optimize randomization and blind patients and outcome assessors

OBJECTIVES: To investigate the impact of potential risk of bias elements on effect estimates in randomized trials. STUDY DESIGN AND SETTING: We conducted a systematic survey of meta-epidemiological studies examining the influence of potential risk of bias elements on effect estimates in randomized trials. We included only meta-epidemiological studies that either preserved the clustering of trials within meta-analyses (compared effect estimates …