Sometimes Less Is Not Enough: A Commentary on Greiff et al. (2015).

In this commentary, I discuss some critical issues in the study by Greiff, S.; Stadler, M.; Sonnleitner, P.; Wolff, C.; Martin, R., "Sometimes less is more: Comparing the validity of complex problem solving measures", Intelligence 2015, 50, 100-113. I conclude that-counter to the claims made in the original study-the specific study design was not suitable for deriving conclusions about the validity of different complex problem-solving (CPS) measurement approaches. Furthermore, a more elaborate consideration of previous CPS research was found to challenge Greiff et al.'s conclusions even further. Therefore, I argue that researchers should be aware of the differences between several kinds of CPS assessment tools and conceptualizations when the validity of CPS assessment tools is examined in future research.