Estimating variances of standardized estimators in case-control studies and sparse data

Flanders (J Chron Dis 37: 449-453, 1984) has presented variance estimators for standardized rate ratios obtained from follow-up data. This paper presents and illustrates the use of analogous estimators for case-control data, and discusses and illustrates estimation of standardized ratios and their variances when the data are sparse, as in matched case-control studies.