The purposes of the present study were (a) to examine the comparative validity of a written job knowledge test constructed on the basis of a systematic job analysis with that of a commercial employment test selected in the absence of a prior job analysis for accounting positions and (b) to determine the fairness of each test for minority and nonminority job applicants. Results indicated that the job knowledge test was a valid and unbiased predictor of relevant criteria of job performance while the commercial employment test produced adverse impact and lacked validity. Implications of the results for future research studies and test validation efforts involving differential prediction are discussed. Copyright © 1979, Wiley Blackwell. All rights reserved