Objective: To demonstrate the clinical application of the Korean version of the Modified Barthel Index (K-MBI) using Rasch analysis.
Methods: A total of 276 patients with neurological disorders were assessed with the K-MBI in outpatient clinics. The Rasch partial-credit model was used to generate a keyform based on investigating the psychometric properties of the K-MBI, including dimensionality, precision (person strata and reliability), and hierarchical item difficulty. The Minimal Detectable Change (MDC) in item difficulty was used to establish right-challenging treatment goals and long-term treatment plans.
Results: The findings demonstrated that the Korean version of the MBI satisfied the assumption of unidimensionality. It also showed a hierarchical structure in terms of item difficulty, good reliability (Cronbach alpha, 0.92), and approximately five distinct person strata (4.6). The MDC (raw score, 20.1) of the item difficulty of the test items demonstrated equivalent cutoff scores for targeted short-term treatment goals on the keyform, a Rasch-derived display of patient responses. Long-term treatment goals were identified based on the test items of the keyform.
Conclusions: The findings suggest that a Rasch keyform can be applied to clinical practice in Korean settings by identifying clinically and statistically meaningful test items and their step thresholds as short- and long-term goals.
Keywords: Keyform; Modified Barthel Index; Outcome measure (health care); Psychometrics; Rasch analysis; Translational research.