RESUMEN
The five-factor structure is a well-established model for personality. The five traits covary with job-performance and work-relevant outcomes. The practical administration of existing big-five measurement scales is, however, somewhat limited, in a Norwegian setting, as existing scales are impractically large or have unknown psychometric properties. Because of this, a new brief Norwegian personality assessment tool has been developed by the Norwegian Armed Forces. This study aims to uncover the psychometric properties of the 50-item Norwegian military personality inventory (NMPI-50) and establish norm data for practical use. The inventory was administered to the 2002 cohort of Norwegian 17-year olds (N = 54,355), and analyzed with factor analysis, graded response models and tests of gender invariance. The five scales of the NMPI-50 showed satisfactory internal consistency, yielded high information across a broad range of the five traits, and conformed to a bi-factor structure with one general factor and five specific factors. The general factor was positively associated with motivation for military service, indicating some measurement bias. The openness scale is less clearly psychometrically defined, compared to the other scales, and both extroversion and openness show some evidence of multidimensionality. The scales also showed scalar invariance between genders except for the openness scale. Overall, the results support the use of NMPI-50 in personnel assessment and research.