Concurrent validity of the MacAndrew Alcoholism Scale: mixed-group validation

The concurrent validity of the MacAndrew Alcoholism Scale (MAC) was assessed using the mixed-group validation procedure described by Dawes and Meehl (1966). Using mixed groups consisting of different proportions of individuals likely to become alcoholic, classified according to their family histories of probable alcohol abuse, the proportions of subjects exceeding various MAC cutting scores were observed. Depending upon the base rates that were assumed, validity coefficients ranging from .82 to 1.02 were obtained when a MAC cutting score of 24 was used. These values are comparable to concurrent validity estimates obtained using known alcoholics.