Much of the evidence in support of job characteristics theory is limited to incumbent reports of job characteristics. In this study, job characteristics data from three independent sources--incumbents, ratings from job descriptions, and the Dictionary of Occupational Titles--were used. Convergent validities of incumbent reports with other sources were quite modest. Although incumbent reports of job characteristics correlated significantly with several employee outcomes (job satisfaction, work frustration, anxiety on the job, turnover intentions, and number of doctor visits), the other sources showed few significant correlations, except for number of doctor visits. Caution is urged in the use of incumbent self-reports of job characteristics as indicators of actual work environments. New methods for studying job characteristics are suggested.