Psychometric Evaluation of the Korean Social Health Scale for the Elderly: A Rasch Analysis of Item Level Validity.

Abstract

Rationale, aims and objectives: This study aims to evaluate the psychometric properties of the Korean Social Health Scale for the Elderly (K-SHSE) using Rasch analysis, to ensure its validity and reliability in measuring social health among older Korean adults.

Methods: A total of 300 community-dwelling adults aged 55 and older in Korea completed the K-SHSE through an online survey. Rasch analysis was conducted using the Partial Credit Model to assess unidimensionality, item fit, difficulty hierarchy, rating scale functioning, precision and differential item functioning (DIF). Analyses were performed separately for the three subdomains: Social Support (SS), Social Adjustment (SA), and Perceived Environmental Resources (PER).

Results: Of the 25 original items, 10 were excluded due to misfits statistics. The final scale retained 15 items across the three subdomains. All subdomains satisfied the assumption of unidimensionality. The SS domain demonstrated strong reliability and person separation, while the SA and PER domains showed limited discriminative ability. Four items displayed statistically significant DIF by sex. The item difficulty hierarchy aligned with theoretical expectations, and no significant floor or ceiling effects were observed.

Conclusion: All domains of the K-SHSE demonstrated acceptable psychometric properties for assessing social health among older adults in Korea, with particularly strong performance in the SS domain. Although some items exhibited DIF or showed limited reliability, their inclusion did not bias the measurement model. These findings support the use of the K-SHSE as a valid and reliable tool for evaluating social health in both research and practical settings.