title: Power calculation for case-cohort studies with nonrare events.
abstract: Case-cohort design has been advocated in many epidemiologic studies when studying rare diseases or events. In this design, with a rare event, all the events are selected for risk-factor assessment. When the event is not rare, it is desirable to consider a generalized case-cohort design, where only a fraction of events are sampled. We provide a valid test statistic to compare hazards functions between two samples for this generalized design and give a method for calculating power. Our result generalizes the result in Cai and Zeng (2004, Biometrics60, 1015-1024), and it shows numerically that efficiency loss due to sampling only part of the events is very low under nonrare-events situation.
authors.affiliation: Department of Biostatistics, University of North Carolina at Chapel Hill, North Carolina 27599-7420, USA.
authors.forename: Jianwen
authors.initials: J
authors.lastname: Cai
authors.forename: Donglin
authors.initials: D
authors.lastname: Zeng
mesh_terms: D000465:Algorithms; D016022:Case-Control Studies; D015331:Cohort Studies; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D035583:Rare Diseases / Q000453:epidemiology*