Reliability and validity of the Japanese version of the Caregiving Interface Work Scale in employed Japanese family caregivers

Aim This study aimed to develop a Japanese version of the Caregiving Interface Work Scale (J‐CIWS) for use with employed Japanese family caregivers. Methods Permission was obtained from the developer of the original CIWS. The CIWS contains 20 items: 10 measuring care interface work (CIW) and 10 measuring work interface care (WIC). Responses are measured on a five‐point Likert scale. The J‐CIWS was developed through forward‐ and back‐translation and cognitive interviews of employed family caregivers. An internet survey was conducted with 116 employed family caregivers, and 78 participants answered a retest. Questionnaire items included the J‐CIWS and demographic factors. Factor analysis was conducted to determine the J‐CIWS factor structure. Validity was assessed based on known‐groups, convergent and discriminant validity. Internal consistency was examined by calculating Cronbach's α. Test–retest reliability was examined by calculating the Pearson's correlation coefficient. Results The mean participant age was 50.3 years; 74 (63.8%) were male. The average weekly working and caregiving hours were 41.6 and 12.1 h, respectively. Confirmatory factor analysis supported the original two‐factor model. High internal consistency (Cronbach's alpha >0.90) and sufficient test–retest reliability (weighted κ score >0.45) were demonstrated for both subscales. Convergent and discriminant validity were acceptable for the two subscales (CIW and WIC). Conclusions This study confirmed the usefulness of the CIWS within a Japanese context. The J‐CIWS may be useful for evaluating the extent of the conflict between work and care among employed family caregivers. Geriatr Gerontol Int 2021; 21: 254–261.