Security in the Interparental Subsystem (SIS) Scale: Psychometric Characteristics in a Sample of Portuguese Adolescents

The Security in the Interparental Subsystem Scale (SIS) is based on emotional security theory. This study examined the psychometric properties of an adaptation of the SIS to a sample of Portuguese adolescents (60.3 % girls; 10 to 18 years old; Mage = 13 years; N = 229), recruited in public schools. Discriminant and concurrent validity were assessed by analyzing SIS dimensions associations with adolescents' exposure to interparental conflict (IC), and psychological adjustment, respectively. Exploratory and confirmatory factor analyses of the SIS supported a six-factor solution, with satisfactory internal consistency. Evidence for discriminant and concurrent validity was provided: most SIS dimensions significantly discriminated between adolescents exposed to higher vs. lower levels of IC; and a significant positive association between emotional reactivity and adolescents' externalizing symptoms was found. These findings suggest that the SIS is a reliable tool for assessing adolescents' emotional insecurity in the interparental relationship within the context of this sample.