Abstract
BACKGROUND: Caregiver self-efficacy is crucial in improving patient outcomes and caregiver well-being, but there is a lack of suitable scales to assess this concept within the context of Chinese culture. This study aimed to cross-culturally translate the Caregiver Self-Efficacy in Contributing to Patient Self-Care (CSE-CSC) Scale and evaluate its psychometric properties using classical test theory and item response theory. METHODS: The CSE-CSC scale was adapted using Brislin's translation model after obtaining authorization from the original author. A multicenter, cross-sectional study was conducted to assess the psychometric properties of this scale. Classical test theory was used to evaluate reliability (internal consistency, test-retest reliability), validity (content validity, structural validity, convergent validity), and floor and ceiling effects. Item response theory was employed to assess the fit of the rating scale model, reliability, item difficulties, and measurement invariance. RESULTS: The translation and cultural adaptation process was completed. Classical test theory demonstrated good internal consistency (Cronbach's α = 0.935) and test-retest reliability (ICC from 0.784 to 0.829, p<0.001). The I-CVI and K* of each item ranged from 0.875 to 1.00 and 0.871 to 1.00. The first-order 2-factor model fit well (χ(2)/df = 3.71, RMSEA = 0.082, SRMR = 0.032, CFI = 0.973, TLI = 0.60). Convergent validity showed that the CSE-CSC scores had a strong positive correlation with three separate scales of the CC-SC-CII. There was no floor and ceiling effect in this scale. Rasch analysis showed that the CSE-CSC scale demonstrated a good fit to the rating scale model and exhibited excellent reliability (person/item separation index>2, person/item reliability coefficients>0.8). The Wright map showed that item difficulty matched the respondents' measured abilities. The analysis of differential item functioning (DIF) showed that all items were comparable in gender. CONCLUSIONS: This study indicated that the CSE-CSC scale had good reliability, validity, difficulty degree, and measurement invariance. The CSE-CSC scale can be used to measure caregiver self-efficacy of Chinese patients with multiple chronic conditions.