Problems with using capture-recapture in epidemiology: an example of a measles epidemic.

Capture-recapture is becoming widely used in epidemiology to estimate disease prevalence or sizes of population at risk. When such estimates are obtained from uncontrolled observation of existing lists, a huge act of faith is required, usually without any scientific justification. Fitting of loglinear models appears to offer some hope but contains major problems of analysis and interpretation. These are illustrated by reanalysis of data on a measles epidemic-see McGilchrist et al. 1996 [J Clin Epidemiol 49, pp. 293-296]--for which the wrong model was selected. It is argued that the measles lists contained so few overlaps that no reliable information is provided by that study about the size of the epidemic.