title: Choosing an appropriate unit of analysis in trials of interventions that attempt to influence practice.
abstract: The choice of an appropriate unit of analysis in evaluations in health policy is problematic and errors are frequently made which may undermine study conclusions. This paper describes the structure of randomized trials, issues concerning randomization and replication, and the factors that should be considered when deciding upon the appropriateness of a unit of analysis.
authors.affiliation: Department of Health Sciences & Clinical Evaluation, University of York, UK.
authors.forename: J
authors.initials: J
authors.lastname: Wood
authors.forename: N
authors.initials: N
authors.lastname: Freemantle
mesh_terms: D003627:Data Interpretation, Statistical; D006291:Health Policy; D006302:Health Services Research / Q000379:methods*; D015233:Models, Statistical; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D006113:United Kingdom