Computing Mean Cost Ratings (MCR)

Abstract

The Mean Cost Rating (MCR) measures the differentiation ability of those variables or groups of variables used in construct ing parole prediction or base expectancy tables. The literature of the past two decades suggests that it represents perhaps the most satisfactoiy statistical index of predictive selectivity. Its use has been limited, however, by its complex method of computa tion. The MCR is explained and a simplified procedure for com puting it is offered. In addition, the MCR is compared with Chi square, the J-value, and the Index of Predictive Selectivity, which have also been used to determine the selective ability of factors in the construction of prediction tables.