A short-form personality measure for military personnel selection: Psychometric investigation and perspectives on usage

Abstract

This doctoral thesis aimed to evaluate the psychometric properties and the practical use of a newly developed self-report personality measure for the Armed Forces, the Norwegian Military Personality Inventory (NMPI). Three published studies contributed to this end. Study 1 explored associations between candidate personality traits and leadership competency ratings at an officer selection program. This study also validated the NMPI-80, the first NMPI version, by correlating it with the well-established NEO-PI-3. Results showed that extroversion (+) and openness (-) emerged as predictors of ratings. Strong correlations between the two personality measures supported the construct validity of the NMPI-80. Study 2 used the NMPI-80 to investigate personality traits among special forces personnel. The findings did not show any difference in mean scores across Army-affiliated operators (FSK), Navy-affiliated operators (MJK), and support personnel. The operators had lower mean extroversion and agreeableness scores, as well as higher emotional stability scores, than Study 1 participants. Study 3 investigated the psychometric properties of the NMPI-50, the finalized NMPI version, by analyzing responses from an age cohort undergoing the conscript selection. Factor analyses, graded response models, and tests of measurement invariance revealed adequate reliability and validity. Although the measure does not generate rich individual profiles, the NMPI may support rater-based selection methods. The NMPI may also be used in a statistical combination of predictors for large-scale conscript selection. However, future predictive validity studies should govern best practice. The thesis expands military psychology by providing empirical studies that are scarcely obtainable in published literature (Studies 1 and 2). Further, it presents comprehensive psychometric analyses (Study 3). The conclusion emphasizes the importance of a continued scientific approach to specifying and measuring human factors relevant for military activities. The NMPI holds sound psychometric properties, although challenges of using self-report are acknowledged.