THE EFFECT OF RECORD LINKAGE ERRORS ON STATISTICAL INFERENCE IN COHORT MORTALITY STUDIES

The advent of computerized record linkage methodology has facilitated the conduct of cohort mortality studies in which exposure data in one database are electronically linked with mortality data from another database. In this article, the impact of linkage errors on estimates of epidemiological indicators of risk such as standardized mortality ratios and relative risk regression model parameters is explored. It is shown that these indicators can be subject to bias and additional variability in the presence of linkage errors, with false links and nonlinks leading to positive and negative bias respectively in estimates of the standardized mortality ratio. Although linkage errors always increase the uncertainty in the estimates, bias can be effectively eliminated in the special case in which the false positive rate equals the false negative rate within homogeneous states defined by cross-classification of the covariates of interest.