Advocates of multiple criteria contend that measures of demonstrably different variables should
not be combined. As Cattell (1957) put it, "Ten men and two bottles of beer cannot be added to
give the same total as two men and ten bottles of beer" (p. 1l).Consider a study of military
recruiters (Pulakos, Borman, & Hough, 1988). In measuring the effectiveness of the recruiters, it
was found that selling skills, human relations skills, and organizing skills all were important and
related to success. It also was found, however, that the three dimensions were unrelated to each
other-that is, the recruiter with the best selling skills did not necessarily have the best human
relations skills or the best organizing skills. Under these conditions, combining the measures
leads to a composite that not only is ambiguous, but also is psychologically nonsensical. Guion
(1961) brought the issue clearly into focus: