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Optimum allocation of samples in strata‐matching case‐control studies when cost per sample differs from stratum to stratum
Author(s) -
Nam JunMo,
Fears Thomas R.
Publication year - 1990
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4780091211
Subject(s) - stratum , estimator , statistics , matching (statistics) , sample size determination , mathematics , odds ratio , variance (accounting) , odds , econometrics , sample (material) , sampling (signal processing) , computer science , logistic regression , economics , biology , filter (signal processing) , chromatography , computer vision , paleontology , chemistry , accounting
We investigate the allocation of samples over strata in case‐control studies with consideration of sampling costs. We consider two situations, typical of strata‐matched case‐control studies. Subject to a fixed total cost we derive optimum allocations that maximize the asymptotic efficiency of Cochran's test, that is, minimize the variance of the maximum likelihood estimator of the common odds ratio when the common odds ratio is one. Our results show that the standard design with equal numbers of cases and controls in each stratum is inefficient when costs per control differ greatly from stratum to stratum. We show that the optimum design suggested in this paper is robust for values of the odds ratio common in epidemiologic studies.