Chapter 8: Against All Evidence: General and Specific Ability in Human Resources Management

For more than 100 years there has been an ongoing dispute about the measurement and utility of general cognitive ability (g) versus specific abilities (s) in human resources management (HRM), particularly for employee selection. The dispute centers around three basic issues: (1) the development and measurement of g versus s, (2) the absolute and relative contributions of general and specific factors to the measurement of abilities, and (3) the utility of these general and specific abilities in HRM in predicting occupational outcomes.

While the notion of specific abilities is quite old (Galton, 1869; Spearman, 1904, 1927; Thurstone, 1938), proponents have advocated their equal or greater importance relative to general ability. The authority and tenacity of this view has accelerated since World War II, in research, practice, and especially, the popular press. The conventional wisdom from many researchers and practitioners is that specific abilities exist; they can be measured reliably and can be differentially weighted to predict different occupational and educational outcomes. Let there be no mistake, the results from the HRM, measurement, and occupational performance literature directly address these issues, with clear, consistent and unequivocal results. Simply stated, the empirical data do not support the conventional wisdom. The empirical evidence demonstrates that: (1) g is pervasive, that is, it can be measured consistently, accurately, and routinely across a wide-range of tests, situations, and methods, while s cannot; (2) the amount of g measured in test batteries is frequently 50% or more of the reliable variance, while the amount of s is usually much less than 10%, and, when considered together, the relative magnitude of g is often five times greater than s; and (3) g is the predominant source of pre-dictiveness in cognitive ability tests (e.g., Jensen, 1998), with s often adding little to no prediction of educational, training, and job performance outcomes (e.g., Ree & Earles, 1991; Ree, Earles, & Teachout, 1994).