Psychometric Properties and Measurement Invariance of the Youth Psychopathic Traits Inventory - Short Version among Portuguese Youth

This study aimed to examine the psychometric properties of the Youth Psychopathic Traits Inventory - Short version (YPI-S) among a mixed-gender sample of 782 Portuguese youth (M = 15.87 years; SD = 1.72) collected in a school context. Exploratory and confirmatory factor analysis offered support for the expected 3-factor structure. Partial cross-gender measurement invariance and cross-sample measurement invariance of the YPI-S using a forensic sample of institutionalized males was established. The Portuguese version of the YPI-S showed adequate psychometric properties in terms of internal consistency, mean inter-item correlation, corrected item-total correlation, convergent validity, and discriminant validity. In support for criterion-related validity, the YPI-S also showed statistically significant associations with self-reported conduct disorder symptoms, alcohol abuse, and drug use. In terms of known-groups validity, males from the school sample scored lower than males from the forensic sample and higher than females from the school sample. The YPI-S seems to be a valuable brief and psychometrically reliable and valid self-report measure, which can be used to assess psychopathic traits in diverse samples of youth.