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Weighting methods for population‐based case–control studies with complex sampling

Summary.  Complex sample designs, involving stratified and/or multistage sampling with sample weighting, along with frequency matching, are used to select controls or cases for case–control studies. Examples that motivated this paper are the Kaposi sarcoma case–control study that was conducted in Sicily and the US kidney cancer case–control study. Survey design‐based approaches can be inefficient for the analysis of case–control studies with frequency matching. We propose a weighting method that post‐stratifies control sample weights to the estimated population distribution of the matching variables among cases. This weighting maintains the efficiency of frequency matching. The method proposed is evaluated by using simulation studies and is applied to the two case–control studies.