In this commentary, we reviewed two clinical validation studies on the Wechsler Scales conducted by Weiss and colleagues. These researchers used a rigorous within-battery model-fitting approach that demonstrated the factorial invariance of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) and Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) across populations. Beyond the important finding of invariance across populations, however, these studies did not provide much additional clarification about exactly what is and what is not measured by the WISC-IV and WAIS-IV vis-a-vis an overarching empirically validated theory of the structure of cognitive abilities. To that end, we argued that a better understanding of the cognitive constructs (both broad and narrow) measured by the Wechsler scales or invariance across selection of variables is necessary and will require theory-driven joint or cross-battery confirmatory factor analysis. Recommendations for conducting this type of research were offered within the context of the Cattell-Horn-Carroll theory of cognitive abilities. (Contains 5 tables.)