The German MMPI-3 : cross-language psychometric evaluation using a bilingual within-person design

Abstract

The Minnesota Multiphasic Personality Inventory-3 (MMPI-3; Ben-Porath & Tellegen, 2020a) describes individual differences in maladaptive traits across hierarchical scale sets and is a standard instrument used in research and applied settings. Using a single-group bilingual design (N = 37), we compared a developmental version of the German MMPI-3 (Engel & Proyer, 2026) with the English original to evaluate translation equivalence. Following international test adaptation guidelines, we examined item- and scale-level equivalency, using item endorsement indices, discriminant functioning, reliability estimates, intraclass correlations, and mean-level differences. Most items showed comparable psychometric functioning across versions. Twenty items (6.0%) were identified as candidates for revision; following expert review, 14 items (4.2%) were ultimately revised. Overall, scale scores and profile similarity indicated high cross-language agreement. These findings provide preliminary support for the German MMPI-3 while they identify specific items requiring refinement.