title: Apparent change in caseness in longitudinal studies.
abstract: Unless positive responses are verified at a second stage of data collection, a questionnaire-based survey has limited ability to assess change in caseness in a longitudinal study of a condition of low prevalence, assuming imperfect validity of the survey instrument.
authors.affiliation: Centre for Adolescent Health, Royal Children's Hospital, Melbourne, Victoria, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Selzer
authors.forename: J B
authors.initials: JB
authors.lastname: Carlin
mesh_terms: D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D015233:Models, Statistical; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*