title: Sample size/power calculation for stratified case-cohort design.
abstract: The case-cohort (CC) study design usually has been used for risk factor assessment in epidemiologic studies or disease prevention trials for rare diseases. The sample size/power calculation for a stratified CC (SCC) design has not been addressed before. This article derives such result based on a stratified test statistic. Simulation studies show that the proposed test for the SCC design utilizing small sub-cohort sampling fractions is valid and efficient for situations where the disease rate is low. Furthermore, optimization of sampling in the SCC design is discussed and compared with proportional and balanced sampling techniques. An epidemiological study is provided to illustrate the sample size calculation under the SCC design.
authors.affiliation: Applied Statistics, Department of Mathematical Sciences, The University of Memphis, Memphis, TN, U.S.A.; Department of Biostatistics, CSL Behring, King of Prussia, PA, U.S.A.
authors.forename: Wenrong
authors.initials: W
authors.lastname: Hu
authors.forename: Jianwen
authors.initials: J
authors.lastname: Cai
authors.forename: Donglin
authors.initials: D
authors.lastname: Zeng
mesh_terms: D015331:Cohort Studies; D003198:Computer Simulation; D003327:Coronary Disease / Q000453:epidemiology*; D015340:Epidemiologic Research Design; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D035583:Rare Diseases / Q000191:economics / Q000453:epidemiology*; D018570:Risk Assessment / Q000379:methods*; D018401:Sample Size; D020521:Stroke / Q000453:epidemiology*
keywords: case-cohort design; power calculation; sample size; sampling technique; stratified case-cohort design