Psychometric analysis of the Salutogenic Health Indicator Scale (SHIS) in adolescents

Aim: The aim of this study was to test the psychometric properties of the Salutogenic Health Indicator Scale (SHIS) in an adolescent population. Methods: The investigation was performed among Swedish students aged 13-15 years (n = 817; 58% girls). The SHIS was assessed for respondent acceptability, and its psychometric properties were evaluated according to classical test theory (regarding unidimensionality, targeting, reliability, and external construct validity). Results: The adolescents found it easy to complete the questionnaire, which was completed in an average of 4 minutes. Exploratory factor analysis, which is based on polychoric correlations, identified one factor, supporting the instrument's unidimensionality. Floor/ceiling effects were 1/2 3.3%. Reliability estimates yielded a Cronbach's alpha value of 0.93; the test-retest reliability (n = 50; 2-week interval) coefficients were 0.89 for the total SHIS score and 0.52-0.79 for item scores. Spearman correlations with other variables were based on a priori expectations (self-rated general health, 0.595; depressive symptoms, '0.773; anxiety, '0.577; and sleep problems, 0.519). Conclusions: Our observations support both the acceptability and the psychometric properties of the SHIS as a brief, unidimensional assessment tool for salutogenic health in adolescents. Further studies using modern test theory are needed to better understand the measurement properties of the SHIS, including the functioning of its response categories and its comparability between adolescents and adults.