The psychometrics and validity of the Junior Temperament and Character Inventory in Portuguese adolescents.

Personality traits related to persistence and self-regulation of long-term goals can predict academic performance as well or better than measures of intelligence. The 5-factor model has been suggested to outperform some other personality tests in predicting academic performance, but it has not been compared to Cloninger's psychobiological model for this purpose. The aims of this study were, first, to evaluate the psychometric properties of the Junior Temperament and Character Inventory (JTCI) in adolescents in Portugal, and second, to evaluate the comparative validity of age-appropriate versions of Cloninger's 7-factor psychobiological model, Costa and McCrae's five-factor NEO-Personality Inventory-Revised, and Cattell's 16-personality-factor inventory in predicting academic achievement. All dimensions of the Portuguese JTCI had moderate to strong internal consistency. The Cattell's sixteen-personality-factor and NEO inventories provided strong construct validity for the JTCI in students younger than 17 years and for the revised adult version (TCI-Revised) in those 17 years and older. High TCI Persistence predicted school grades regardless of age as much or more than intelligence. High TCI Harm Avoidance, high Self-Transcendence, and low TCI Novelty Seeking were additional predictors in students older than 17. The psychobiological model, as measured by the JTCI and TCI-Revised, performed as well or better than other measures of personality or intelligence in predicting academic achievement.