title: Developments in cluster randomized trials and Statistics in Medicine.
abstract: The design and analysis of cluster randomized trials has been a recurrent theme in Statistics in Medicine since the early volumes. In celebration of 25 years of Statistics in Medicine, this paper reviews recent developments, particularly those that featured in the journal. Issues in design such as sample size calculations, matched paired designs, cohort versus cross-sectional designs, and practical design problems are covered. Developments in analysis include modification of robust methods to cope with small numbers of clusters, generalized estimation equations, population averaged and cluster specific models. Finally, issues on presenting data, some other clustering issues and the general problem of evaluating complex interventions are briefly mentioned.
authors.affiliation: Medical Statistics Group, School of Health and Related Research, University of Sheffield, Sheffield, UK. m.j.campbell@sheffield.ac.uk
authors.forename: M J
authors.initials: MJ
authors.lastname: Campbell
authors.forename: A
authors.initials: A
authors.lastname: Donner
authors.forename: N
authors.initials: N
authors.lastname: Klar
mesh_terms: D001499:Bayes Theorem; D001699:Biometry / Q000266:history; D016000:Cluster Analysis; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D015233:Models, Statistical; D011643:Publishing / Q000266:history; D016032:Randomized Controlled Trials as Topic / Q000266:history / Q000706:statistics & numerical data*; D018401:Sample Size