The HEXACO-Middle School Inventory (MSI): A Personality Inventory for Children and Adolescents

We developed and validated a novel measure, the 6-factor personality HEXACO-Middle School Inventory (MSI). We started with a pool of 16 items for each of the six dimensions of the HEXACO. In Study 1, we administered the HEXACO-MSI to 1,089 Italian children and the Observer version to their parents. Using principal component analyses (PCA) and extension factor analysis (EFA), we selected the best eight items for each dimension. Confirmatory factor analysis (CFA) confirmed the 6-factor dimensionality and its invariance. Internal consistency of each dimension was adequate. Convergent and divergent validity were successfully established with a version of the scale filled by parents. Convergent validity was also established with the Big Five Questionnaire Children (BFQ-Children) whereas divergent validity was less clearcut. Conscientiousness, Honesty-Humility, and eXtraversion demonstrated predictive validity of school marks (criterion validity). In Study 2 (N = 317), we replicated dimensionality, internal consistency, and established test-retest reliability of each dimension in two measurements at a 1 month distance. The HEXACO-MSI showed a clear personality structure organized in six traits, and evidence of predictive validity of relevant school criteria particularly via Conscientiousness, Honesty-Humility, and eXtraversion.