OBJECTIVE: Statisticians have criticized the use of significance testing to compare the
distribution of baseline covariates between treatment groups in randomized controlled trials …

FOR THE LAST HALF-CENTURY, RANDOMIZED CLINICAL trials (RCTs) have been the
“gold standard” of evalu-ating the efficacy or effectiveness of clinical interventions …

Over the last twenty years there has been a dramatic upsurge in the application of meta-
analysis to medical research. This has mainly been due to greater emphasis on evidence …

The role of observational studies in the evaluation of treatments is a long-standing and
contentious topic. 1 In this issue of the Journal, Concato et al. 2 and Benson and Hartz3 …

Biases in systematic reviews and meta‐analyses may be examined in 'meta‐
epidemiological'studies, in which the influence of trial characteristics such as measures of …

The results of a randomized clinical trial can be reported using relative and/or absolute
estimators of treatment effect. These various measures convey different information, and the …

For meta‐analysis, substantial uncertainty remains about the most appropriate statistical
methods for combining the results of separate trials. An important issue for meta‐analysis is …

Flaws in the design of randomized trials may bias intervention effect estimates and increase
between-trial heterogeneity. Empirical evidence suggests that these problems are greatest …

This paper examines eight published reviews each reporting results from several related
trials. Each review pools the results from the relevant trials in order to evaluate the efficacy of …

Objective To synthesise evidence on the average bias and heterogeneity associated with
reported methodological features of randomized trials. Design Systematic review of meta …