ASSESSMENT OF EXPOSURE MISCLASSIFICATION BIAS IN CASE-CONTROL STUDIESUSING VALIDATION DATA

It has recently been shown that the bias due to misclassification of a binary exposure in case-control studies can be simply expressed in te rms of so-called quality indices. Quality indices are measures of the degree of misclassification that are symmetric with respect to the tru e and measured exposure. They can be estimated from sub study validati on data and used to estimate the bias. Bias is not present if quality indices are nondifferential with respect to cases and controls. In thi s article the sampling distribution of these indices is investigated b y developing formulae for their standard errors and these formulae are used to derive the standard error of the estimated bias. Simulation s tudies are used to confirm the validity of the formulae. The formulae are used to assess the bias in two studies of risk factors for Sudden infant Death Syndrome (SIDS) and can be applied to the assessment. of diagnostic tests. Copyright (C) 1997 Elsevier Science Inc.