title: Internal validation of models with several interventions.
abstract: In cost-effectiveness analyses, models are used typically to synthesize the best available data and/or extrapolate beyond clinical trial data. Ideally, models should be validated both internally and externally. The purpose of this paper is to suggest a test for internal validation of models where several interventions for the same clinical indication are compared. To the best of our knowledge, such a specific test does not yet exist. There are four versions of the test, which consider the relationship between incremental downstream costs and effects in the case of a single or several endpoints. We apply two versions of the validation test to published cost-effectiveness analyses of physical activity programs and demonstrate internal validity of the model in one study and lack of internal validity of the model in the other study.
authors.affiliation: Frankfurt School of Finance and Management, Sonnemannstr. 9-11, 60314, Frankfurt am Main, Germany, a.gandjour@fs.de.
authors.forename: Afschin
authors.initials: A
authors.lastname: Gandjour
authors.forename: Amiram
authors.initials: A
authors.lastname: Gafni
mesh_terms: D000328:Adult; D003362:Cost-Benefit Analysis; D015444:Exercise; D006801:Humans; D055686:Metabolic Equivalent; D008875:Middle Aged; D018803:Models, Economic; D019057:Quality-Adjusted Life Years; D015203:Reproducibility of Results