Objectives The goal of this study is to identify, analyse and classify interventions to improve
adherence to reporting guidelines in order to obtain a wide picture of how the problem of …

Background Modeling count and binary data collected in hierarchical designs have
increased the use of Generalized Linear Mixed Models (GLMMs) in medicine. This article …

In cluster-randomized trials, groups of individuals rather than individuals are randomized to
different interventions. The groups may be, for example, schools, villages, medical practices …

Abstract Background Cluster randomised trials (CRTs) are commonly analysed using mixed-
effects models or generalised estimating equations (GEEs). However, these analyses do not …

There is currently a lot of interest in pilot studies conducted in preparation for randomised
controlled trials. This paper focuses on sample size requirements for external pilot studies …

Background The stepped wedge (SW) cluster randomized controlled trial (CRCT) design is
being used with increasing frequency. However, there is limited published research on the …

Background Increasing patient-reported outcome measures in the 1980s and 1990s led to
the development of recommendations at the turn of the millennium for standardising …

This article reviews the essential ingredients and innovations in the design and analysis of
group-randomized trials. The methods literature for these trials has grown steadily since they …

Background Clustering of observations is a common phenomenon in epidemiological and
clinical research. Previous studies have highlighted the importance of using multilevel …

Objectives To assess the quality of reporting and accuracy of a priori estimates used in
sample size calculations for cluster randomized trials (CRTs). Study Design and Setting We …