"Today the validity of different personnel measures can be determined with the aid of 85 years of research. The most well-known conclusion from this research is that for hiring employees without previous experience in the job the most valid predictor of future performance and learning is general mental ability, i.e., intelligence."

This quote is from an article published recently by Frank Schmidt and John Hunter in the American Psychological Association journal, "Psychological Bulletin." Schmidt and Hunter compared 19 different selection methods ranging from intelligence to graphology which had been used in making decisions about hiring, training, and developing employees.

Comparisons of general mental ability and job performance for individuals and small samples can vary widely and be quite misleading. However, when large samples can be studied or when smaller studies can be studied cumulatively, as Schmidt and Hunter did for this article, the pattern becomes quite clear.

One of the authors, Hunter, had completed a large "meta-analysis," i.e., a study accumulating results over many separate studies, in a project for the U.S. Department of Labor which was used as an important part of this report. Hunter's project involved over 32,000 employees in 515 "widely diverse civilian jobs." Hunter found correlations between "general mental ability" and job performance of .58 for professional-managerial jobs, .56 for complex technical jobs, .51 for medium complexity jobs, .40 for semi-skilled jobs, and .23 for unskilled jobs.

What Hunter showed is that in the long run, up to 33% of managerial job performance can be accounted for by estimates of the manager's general mental ability. There is no other applicant characteristic or combination of characteristics which can account for such a high proportion of managerial success. Certainly job experience remains an important factor. Yet in a rapidly changing and increasingly challenging world, the ability to learn and develop is a critical element in the formula for organizational success.

Managerial talent is a limiting factor for business success, and, sadly, most businesses are starved for managerial talent. However, Schmidt and Hunter have made the task of identifying management talent easier.

The data are clear. The most valid personnel predictor of future performance and learning for managerial applicants is general mental ability, i.e., intelligence. General mental ability can increase the odds of successful managerial performance more than any other measure. If one takes into account the importance of building a pool of managerial talent for future promotions, the importance general mental ability in making selection decisions becomes even more critical.

Kenneth L. Davis, Ph.D.

March 18, 1999