5.5 Air force recruits

In a study carried out at the Human Resources Laboratory at Brooks Air Force Base under the supervision of Malcolm Ree, Eddy (1988) examined relations between the TKIM and the Armed Services Vocational Aptitude Battery (ASVAB) for a sample of 631 Air Force Recruits, 29 percent of whom were females, and 19 percent of whom were members of a minority group. The ASVAB is a multiple-aptitude battery used for selection of candidates into all branches of the United States Armed Forces. Prior studies of the ASVAB suggest that it is a typical measure of cognitive skill, with correlations between ASVAB scores and other cognitive skill measures of about .7. Factor-analytic studies of the ASVAB also suggest that it appears to measure the same verbal, quantitative, and mechanical skills as the Differential Aptitude Tests, and the same verbal and mathematical knowledge as the California Achievement Tests.

Eddy's (1988) study showed small correlations between tacit knowledge and ASVAB subtests. The median correlation was -.07, with a range from .06 to -.15. Of the 10 correlations, only two were significantly different from zero, despite the large sample size of 631 recruits. A factor analysis of all the test data, followed by oblique rotations, yielded the usual four ASVAB factors (vocational-technical information, clerical/speed, verbal skill, and mathematics) and a distinct tacit-knowledge factor. The factor loading for the TKIM score on the tacit-knowledge factor was .99, with a maximum loading for scores on the four ASVAB factors of only .06. Upon oblique rotation, the four ASVAB factors were moderately intercorrelated, but the correlations between the tacit knowledge factor and the four ASVAB factors were near zero (.075, .003, .096, .082).

An additional point about these results concerns the possibility that measures of tacit knowledge might identify potential managers from nontraditional and minority backgrounds whose practical knowledge suggests that they would be effective managers, even though their performance on traditional selection measures such as cognition tests does not. Eddy (1988) did not report scores separately by race and sex, but did report correlations between scores and dummy variables indicating race and sex. Significant correlations in the .2 to .4 range between ASVAB subtest scores and both race and sex indicate that on the ASVAB, minority-group members scored more poorly than majority group members, and women scored more poorly than men. Nonsignificant correlations between tacit knowledge and both race (.03) and sex (.02), however, indicate comparable levels of performance on the tacit-knowledge measures between minority and majority-group members and between females and males.