AbstractManyjob design studies incorporate a direct measure of individual differences to test the contingency hypothesis of Hulin and Blood. This study examines two basic approaches to the measurement of potential moderators of the relationship between job design and job satisfaction. One method involved independent determination of a work value system, and predicted job satisfaction of subjects in an experimental study on job enlargement. The second method, strength of higher order needs, did not yield the same results as did the first. This difference shows that choice of an operational definition of individual differences affects research findings. For purposes of personnel selection or placement, the work values approach (method one) appears to be more useful than the need strength measure (method two).