Measurement properties of the Korean Short Form of the awareness of age-related change scale among korean older adults: a Rasch analysis
摘要
The Awareness of Age-Related Change Scale (AARC) assesses perceived gains and losses associated with aging. Although a Korean short form has been validated among older adults, the reduction in item number may limit measurement coverage and weaken the interpretability of subscale scores if individual items and response categories do not function as intended. To address this issue, this study used Rasch analysis to evaluate the measurement properties of the Korean 14-item form.
MethodsA face-to-face survey was conducted with Korean adults aged 65 years or older. Data from 395 participants were analyzed. Rasch analyses were performed using the Rating Scale Model. Rasch residual-based dimensionality analysis was used to evaluate whether the prespecified total scale and subscales functioned sufficiently as measurement units. Item difficulty and fit, person–item targeting, rating scale category functioning, and gender-related differential item functioning were also examined.
ResultsThe total 14-item scale did not support a single unidimensional structure, whereas the gain awareness (GA), health-related loss awareness (HRL), and non-health-related loss awareness (NHRL) subscales showed more acceptable dimensionality. Most items fit the Rasch model, although one gain item related to paying more attention to health and one loss item related to forgetfulness showed underfit. Person–item targeting and precision indices showed low person reliability for GA (0.38) and NHRL (0.49) and modest person reliability for HRL (0.67), suggesting limited precision for individual-level assessment rather than a general weakness of the scale. The five-point response format showed disordered thresholds, suggesting limited distinction among adjacent intermediate categories. Gender-related differential item functioning was statistically significant for one item, but its effect size was negligible.
ConclusionThe Korean short-form AARC is better interpreted as a subscale-based measure than as a single total score. Further validation and refinement are needed, particularly regarding selected item wording, item coverage, response category functioning, and subgroup comparability, before the scale is used for precise individual-level assessment.