Psychometric properties of the German version of the Self-Image Scale (SIS-D)

BACKGROUND: The Self-Image Scale is a self-report measure originally developed for use in women with cancer. Two subscales assess appearance satisfaction (self-acceptance) and perceptions of partners’ acceptance of their appearance (partner-acceptance). This study aimed to increase the Self-Image Scale’s utility by 1) confirming the two-factor structure of the German version of the Self-Image Scale, 2) testing measurement invariance across sex and age groups and validity, and 3) gathering general population normative data. METHODS: Confirmatory factor analysis methods were used to examine the proposed two-factor model in a random sample of adults from the general German population (N = 1367). Measurement invariance, scale reliability, and validity were assessed. RESULTS: The original factor structure and measurement invariance across sexes and age groups were supported. Women showed significantly lower self-acceptance than men. Adolescent and young adult women showed higher self-acceptance than senior women. For both sexes, partner-acceptance lowered across successive age cohorts. Internal consistencies were good. CONCLUSIONS: Results support the use of the German version of the Self-Image Scale in research and clinical practice. Research directions include validation in further diseases, collecting normative data across countries, and dyadic research, particularly exploring partner-acceptance across the life span.