The Wechsler Intelligence Scale for Children--Fifth Edition (WISC-V; Wechsler, 2014) provides a general intelligence score, representing "g," and five index scores, reflecting underlying broad factors. Within person differences between the overall performance across subtests and index scores, denoted as index difference scores, are often used to examine profiles of strengths and weaknesses. In this study, the validity of such profiles was examined for the Dutch WISC-V. In line with previous studies, broad factors explained little variance in index scores. A simulation study showed that variation in index difference scores also reflected little broad factor variance. The simulation study further revealed that, as a consequence, a significant discrepancy between an index score and overall performance was accompanied in only 40%-74% of the cases by a discrepancy on the underlying broad factor. Overall, these results provide little support for the validity and thereby clinical use of WISC-V profiles.