Valid cognitive ability measures in the public domain : a convergent validity study of the ICAR16 using the WAIS-IV
One of the main barriers to the utility of the International Cognitive Ability Resource (ICAR) is that no research to date has been conducted on its construct validity using a theory - based individual cognitive assessment battery. The aim of the current study was to examine the relations between the ICAR16 items and the Cattell-Horn-Carroll (CHC) broad abilities as measured by the Wechsler Adult Intelligence Scale--Fourth Edition (WAIS-IV). Research questions include: 1) Is there evidence of the convergent validity of the ICAR16 when compared with a gold-standard individual assessment of cognitive abilities? And, 2) Which CHC constructs are related to the respective ICAR subtests? Data was collected from a convenience sample of university student volunteers (N = 67) and a clinical sample from a university-based assessment center (N = 30) who completed the ICAR Sample Test (ICAR16) and the ten core subtests of the WAIS-IV. To address the first research question, the correlations between the confirmatory-factor estimated general factors from the ICAR16 and WAIS-IV were examined. The model fit the data well ([subscript X]2 (19) = 14.15, p= .78) and revealed a large correlation between the general factors (r =.94, p<.001). The range-and-reliability-corrected correlation between the WAIS-IV FSIQ and the ICAR16 total score was also large (rICAR16, FSIQ=.81 p<.001). To address the second research question, correlational methods of examining convergent and discriminant validity were employed. Evidence from range-and-reliability-corrected correlations suggests that the ICAR16 Letter-Number Series task is most closely related to fluid reasoning (Gf) (r=.70, p<.01) while the Matrix Reasoning, Verbal Reasoning, and Three-Dimensional Reasoning tasks are most closely related to visual-spatial reasoning (Gv) (r=.35- .75). As a point of discriminant validity, all of the ICAR tasks demonstrated the lowest correlations with measures of processing speed (Gs) or working memory (Gsm) (r=.07-.32). Findings suggest that the ICAR16 provides a valid estimate of nonverbal intelligence. Results of the present study suggest that the ICAR16 may not be sensitive enough to discriminate between distinct CHC abilities, though more specific associations may be revealed in a larger sample. The present study provides a foundation for future validation and use of the ICAR.