Use and interpretation of test scores from limited cognitive test batteries: how g + Gc can equal g

Single scores from limited and unbalanced test batteries of cognitive ability can be ambiguous to interpret theoretically. In this study, a limited verbally and knowledge-loaded cognitive test battery, from applicants to the Swedish police academies (N = 1,344), was examined to provide foundations for the use and interpretation of test scores. Three measurement models were compared: one single factor model and two bifactor models, which decomposed the variance of the battery into orthogonal components. The models were evaluated by fit indices and omega coefficients, and then applied to the prediction of academic performance. The overall prediction of all models was similar, although specific abilities also were found to provide substantial predictive validity over and above general intelligence (g). The findings provide support for the use of single scores in applied settings (selection), but suggest that it may be more appropriate to interpret such scores as composites of substantive components, and not just as measures of g.