Validation of the Youth Psychopathic Traits Inventory and Youth Psychopathic Traits Inventory – Short Version Among Incarcerated Juvenile Delinquents Pedro Pechorro 1 & Henrik Andershed 2 & James V. Ray 3 & João Maroco 4 & Rui Abrunhosa Gonçalves 1 # Springer Science+Business Media New York 2015 Abstract The aim of the present study was to examine the psychometric properties of the Youth Psychopathic Traits Inventory (YPI) and of the Youth Psychopathic Traits Inventory – Short version (YPI-S) among Portuguese juvenile delinquents within a forensic sample of 221 incarcerated males (ages 13–20 years). Confirmatory Factor Analysis sup- ported the three-factor structure of the YPI and YPI-S, and the reliability of both instruments was good for the majority of subscales and factors. The YPI and YPI-S and their subscales showed good criterion, external, and divergent validity. That is, positive associations were found with a number of external criteria including Conduct Disorder, crime seriousness, and violent crimes. Total and subscale scores on both YPI versions were positively related to the Antisocial Process Screening Device, the Inventory of Callous-Unemotional Traits, and the Child and Adolescent Taxon Scale. Finally, both the YPI and YPI-S were mostly unrelated to the Social Anxiety Scale for Adolescents. Overall, the YPI-S presented less problems with reliability, but weaker relations to external correlates. These findings justify the use of the YPI and the YPI-S among incarcerated youths. Keywords Assessment . Youth Psychopathic Traits Inventory (YPI) . Youth Psychopathic Traits Inventory - Short version (YPI-S) . Juvenile delinquency . Validation Psychopathy has become important in the identification of a more serious and persistent subgroup of antisocial youth. Juveniles with high psychopathic traits begin their criminal activities earlier in life, commit more serious crimes, have higher predisposition to use weapons, and their victims sustain greater injury (Frick et al. 2003; Murrie et al. 2004; Pechorro et al. 2014a; Salekin et al. 2004; Vitacco et al. 2007). Psychopathic traits in offenders are associated with more institutional violence (Brandt et al. 1997), higher rates of recidivism, and a shorter time between release and re-offense compared to offenders without these traits (Gretton et al. 2004; Hildebrand et al. 2004; Leistico et al. 2008; Rice and Harris 2013). In turn, juvenile psychopathy has gained importance in forensic theory and practice (Häkkänen-Nyholm and Nyholm 2012; Salekin and Lynam 2010; Vitacco and Salekin 2013). Researchers, borrowing from the established nomological network of adult psychopathy, have modified assessment instruments to make them developmentally appro- priate for use with youth (e.g., Forth et al. 2003; Frick and Hare 2001). Such efforts provide the possibility of a more vast understanding of the etiology of the disorder and of early * Pedro Pechorro ppechorro@gmail.com Henrik Andershed henrik.andershed@oru.se James V. Ray james.ray@utsa.edu João Maroco jpmaroco@ispa.pt Rui Abrunhosa Gonçalves rabrunhosa@psi.uminho.pt 1 School of Psychology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal 2 School of Law, Psychology and Social Work, Örebro University, 70182 Örebro, Sweden 3 Department of Criminal Justice, University of Texas at San Antonio, 501 W Cesar E. Chavez, Blvd., San Antonio, TX 78207, USA 4 ISPA – Instituto Universitário, Rua Jardim do Tabaco, 34, 1149-041 Lisbon, Portugal J Psychopathol Behav Assess DOI 10.1007/s10862-015-9490-1