The Effect of Aptitude and Experience on Mechanical Job Performance

Abstract

The Armed Services Vocational Aptitude Battery (ASVAB) is the test used by the United States military for personnel selection and classification. We evaluated the validity of this selection test to predict mechanical job performance, as measured by five different criteria: a hands-on performance test, a job knowledge test, grade point average in mechanical training, job proficiency ratings, and supervisor ratings. Using a sample of 891 automotive mechanics and 522 helicopter mechanics, we found that a mechanical maintenance composite of the ASVAB predicts hands-on performance, job knowledge, and training grades quite well, with validities corrected for range restriction between .68 and .72; the ASVAB was not as predictive of performance ratings, with validities ranging from .09 to .20. Job experience, measured by time in service, was also important in predicting job performance. No aptitude by experience interaction was found. For hands-on performance and job knowledge, an additional 10 points on the ASVAB composite usually resulted in greater performance than did an additional 12 months of job experience. Conversely, experience was the dominant predictor for performance ratings.