Ascertainment corrected rates: applications of capture-recapture methods.

Accurate rates, though fundamental to epidemiology, are often very difficult to obtain. Incidence, prevalence, and mortality rates have traditionally been established through either passive reporting surveillance systems, through active surveillance systems, or by a combination of the two methods. Typically, when researchers employ these approaches they do not formally evaluate or correct for the degree of underascertainment. Undercount of cases is a potent determinant of rates which we cannot continue to ignore. We believe all rates should be adjusted for underascertainment in order to achieve a truer picture of the risk and risk factors of disease. Here, we present a procedure to ascertainment correct rates based upon well established capture-recapture methods.