title: The design of empirical studies: towards a unified view.
abstract: A broad review is given of the general principles underlying study design with emphasis on applications in medical and epidemiological contexts. The main theme of the paper is that, while the distinction between interventionist studies, that is experiments, and purely observational ones is important, there are many common threads. A wide range of specific applications are used in outline to illustrate the discussion.
authors.affiliation: Nuffield College, Oxford, OX1 1NF, UK. david.cox@nuffield.ox.ac.uk.
authors.forename: David R
authors.initials: DR
authors.lastname: Cox
mesh_terms: D015982:Bias; D004812:Epidemiologic Methods; D016021:Epidemiologic Studies; D006801:Humans; D012107:Research Design
keywords: Bias; Case–control study; Clinical trial; Cohort study; Confounding; Generalizability; Longitudinal study; Metrology; Objectives of study; Prospective study; Randomization; Retrospective study; Specificity