Estimating the Rate of Transfer to a Voluntary Improvement or Rehabilitation Programme Following Capture

Abstract

AbstractA method is developed for determining the effectiveness of counselling individuals to undertake a voluntary improvement or rehabilitation programme following capture. This is achieved by estimating the rate of transfer. Estimates are also obtained of the number who have undertaken the programme previously and those who have not undertaken the programme. For a closed population, the estimated rate of transfer is shown to be unbiased and its variance derived. The estimate is obtained under general conditions and, in the special case, when deaths of drug addicts occur, it is shown that the estimate is approximately unbiased. The theory could also be used to estimate the tag losses/gains due to migration in biological populations when capture‐recapture techniques are used.