A Mokken Scale Analysis of the Last Series of the Standard Progressive Matrices (SPM-LS).

Raven's Standard Progressive Matrices Raven (1941) is a widely used 60-item long measure of general mental ability. It was recently suggested that, for situations where taking this test is too time consuming, a shorter version, comprised of only the last series of the Standard Progressive Matrices (the SPM-LS; Myszkowski and Storme (2018)) could be used, while preserving satisfactory psychometric properties Garcia-Garzon et al. (2019); Myszkowski and Storme (2018). In this study, I argue, however, that some psychometric properties have been left aside by previous investigations. As part of this special issue on the reinvestigation of Myszkowski and Storme's dataset, I propose to use the non-parametric Item Response Theory framework of Mokken Scale Analysis Mokken (1971, 1997) and its current developments Sijtsma and van der Ark (2017) to shed new light on the SPM-LS. Extending previous findings, this investigation indicated that the SPM-LS had satisfactory scalability ( H = 0 . 469 ), local independence and reliability ( M S = 0 . 841 , L C R C = 0 . 874 ). Further, all item response functions were monotonically increasing, and there was overall evidence for invariant item ordering ( H T = 0 . 475 ), supporting the Double Monotonicity Model Mokken (1997). Item 1, however, appeared problematic in most analyses. I discuss the implications of these results, notably regarding whether to discard item 1, whether the SPM-LS sum scores can confidently be used to order persons, and whether the invariant item ordering of the SPM-LS allows to use a stopping rule to further shorten test administration.