Development and validation of the Korea University Social Isolation Scale

Social isolation is a complex phenomenon encompassing behavioral, cognitive, emotional, and functional dimensions that represents a major public health issue. Beyond reduced social contact, it is associated with subjective distress and difficulties in academic and occupational engagement. To address this complexity, we developed and validated the Korea University Social Isolation Scale (KUSIS), a multidimensional tool designed to identify individuals at high levels of social isolation and capture the diverse experiences of isolation.

Following item generation and a pilot study (n = 100), the main validation study was conducted with 206 community-dwelling young adults in Korea. The psychometric properties of the KUSIS were evaluated using exploratory and confirmatory factor analyses, as well as internal reliability and validity. Furthermore, split-sample cross-validation and measurement invariance across gender were conducted. Convergent validity was examined through correlations with the Multidimensional Scale of Perceived Social Support and the Loneliness and Social Isolation Scale. Known-groups validity was assessed by comparing scores of socially isolated (n = 62) and non-socially isolated (n = 144) groups, classified using semi-structured interviews. To confirm classification accuracy, receiver operating characteristic curve analysis was also performed.

Factor analyses supported a three-factor structure with the final nine items: Social Avoidance, Sense of Social Dysfunction, and Sense of Social Disconnection. This structure was generally supported by split-sample cross-validation and was invariant across gender. The KUSIS showed strong internal consistency, with Cronbach’s α, McDonald’s ω, and composite reliability all indicating good reliability. Convergent validity was supported by significant correlations with criterion measures, and known-groups validity was supported by significant differences between socially isolated and non-socially isolated participants. The KUSIS showed strong classification accuracy (area under the curve = 0.937), with a cutoff of 8.5 providing optimal sensitivity (0.887) and specificity (0.826).

The KUSIS is a valid and reliable instrument for assessing multiple dimensions of social isolation among Korean young adults. Its concise structure and empirically derived cutoff scores may help in the identification of socially isolated individuals and offer preliminary guidance for considering different support needs.