Uncertainty in Benefit-Cost Analysis of Supported Employment

A critical, but often overlooked, aspect of benefit-cost analysis is an assessment of the uncertainty inherent in all program evaluation. This uncertainty arises from the estimation of program effects, from the procedures and assumptions used to value those effects, and from variations in the characteristics of the persons served and in the way a program is implemented. In general, the level of uncertainty is highest for evaluations of new prototype programs and decreases as the programs are replicated and serve larger numbers of persons. An understanding of the causes and magnitude of uncertainty is essential for interpreting and using benefit-cost analysis. This is illustrated in the literature pertaining to the benefits and costs of transitional and supported employment where benefit-cost findings have ranged from very positive to mildly negative.