In general, applied psychologists are guided by two principal objective: (1) to demonstrate the utility of their procedures and program and (2) to enhance their understanding of the determinants of job success. In attempting to achieve these twin objective, sometimes composite criteria are used and sometimes multiple criteria are used. Although there has been an enduring controversy over the relation merits of each approach, the two position have been shown to differ in terms of underlying assumptions and ultimate goals. Thus, one or both may be appropriate in a given set of circumstances. In a concluding section of this chapter, several promising research designs are presented that should prove useful in resolving the criterion dilemma and thus in advancing the field.