Using a random sample of 79 theorists selected from among six of Mullins' theory groups, this study attempts to empirically assess the validity of Mullins' theory group classifications. The procedure involved utilizes multiple discriminant analysis based on four demographic-academic variables standardized relative to the publication date of the first major work written by each theorist. Results of the discriminant analysis indicate 70 percent of 40 cases, for whom complete data were available, are correctly classified, based on Mullins' initial categorizations. These results show Mullins' classification schema as having considerable construct validity, as well as demonstrating the utility of using multiple discriminant analysis as a technique for assessing other classificatory systems.