Selection Bias in Population-Based Cancer Case–Control Studies Due to Incomplete Sampling Frame Coverage

摘要

BackgroundIncreasing numbers of individuals are choosing to opt out of population-based sampling frames due to privacy concerns. This is especially a problem in the selection of controls for case–control studies, as the cases often arise from relatively complete population-based registries, whereas control selection requires a sampling frame. If opt out is also related to risk factors, bias can arise.