title: Multistage sampling.
authors.affiliation: Institute for Medical and Biomedical Education, St George's, University of London, London, UK p.sedgwick@sgul.ac.uk.
authors.forename: Philip
authors.initials: P
authors.lastname: Sedgwick
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003625:Data Collection / Q000379:methods*; D055991:Health Records, Personal; D006302:Health Services Research / Q000379:methods*; D006801:Humans; D007258:Informed Consent; D062486:Public Health Surveillance / Q000379:methods*; D011639:Public Opinion; D012042:Registries; D011795:Surveys and Questionnaires; D006113:United Kingdom