Psychometric properties of the Impulsive/Premeditated Aggression Scale in Portuguese community and forensic samples

Abstract Introduction Aggression can be defined according to impulsive or premeditated features. Impulsivity is defined as an uncontrolled and unplanned form of aggression. On the contrary, premeditation requires planning and is goal-oriented. Objective The purpose of this study was to validate the basic psychometric properties of the Impulsive/Premeditated Aggression Scale (IPAS) into European Portuguese. The scale evaluates aggression according to impulsive and premeditated features, which are considered the predominant forms of aggressive behavior, and can be used in community, forensic and clinical settings. Methods Participants from a community sample (n = 957; 424 male) and incarcerated individuals (n = 115, all male) completed the IPAS. Results Internal consistency and reliability indicated that the scale has good psychometric properties in both samples. Data from a principal component analysis (PCA) demonstrated similarities to previous structures reported in the literature. Conclusions The scale demonstrated to be sensitive to the bimodal classification of aggression in community and forensic samples, indicating its utility in the characterization of aggressive patterns