Can we measure homelessness? A critical evaluation of the method of 'capture-recapture'

This paper considers the possibility of accurately measuring the numbers of persons homeless in a given location, at particular times. It is maintained that such data are necessary to the efficient apportioning of resources, but hitherto have been unobtainable through 'traditional' methods of counting. In recent years researchers have advocated the use of the method of 'capture-recapture', a technique which utilizes information from duplicate cases to allow the number of people otherwise unobserved to be calculated. This paper describes and critically evaluates the use of this method in two studies in Plymouth and Torbay, UK.