CAPTURE-RECAPTURE METHODS IN EPIDEMIOLOGIC STUDIES

Medical researchers often are faced with the challenge of estimating t he total number of cases in a population based on incomplete samples. Because of a lack of explicit methods for determining if all cases hav e been counted, indirect methods for estimating the abundance of disea se have been developed. Capture-recapture models are an indirect metho d of estimating population sizes that have been employed in recent epi demiological studies. These methods, derived from techniques developed for studies of animal abundance, estimate the true population size by evaluating the degree of overlap among incomplete lists of cases from existing data sources. Although intuitively appealing, the successful application of these methods is dependent upon a clear understanding of the biology of the disorder involved, the dynamics of the reference population, and the assumptions and robustness of the specific models used. Failure to address these issues can lead to inaccurate and some times misleading results. This article describes some of the strengths and limitations of recapture techniques and provides the reader with a foundation from which to explore the methods in further detail.