Background: The aim of this study was to develop and perform cross-cultural validation of a Japanese version of the Adult Social Care Outcomes Toolkit (ASCOT) four-level Self-Completion questionnaire (SCT4) instrument to measure Social-Care Related Quality of Life. It was important to develop a Japanese version of the ASCOT-SCT4 and validate it in the Japanese context, given the interest in measuring outcomes of social care services in Japan.
Methods: The original version of ASCOT-SCT4 was translated into Japanese following good practice guidelines. Additionally, comments and feedback were obtained from an independent committee engaged in managing and providing social care services to refine the flow of sentences of the newly developed translated version. The resulting version was tested for cross-cultural validation among community-dwelling adults who use social care services to confirm the factorial structure and the scale system of the Japanese version, using Structural Equation Modeling and Item Response Theory.
Results: Vigorous discussion was needed to translate the original version into Japanese especially for the items control over daily life and dignity. These two items were linguistically difficult to express in everyday language so potential participants could easily understand the intended concepts. In the cross-cultural validation, we obtained values for model fit within the acceptable range: between 0.706 and 0.550 for factor loadings, 0.923 for the Comparative Fit Index, 0.910 for the Tucker-Lewis Index, and 0.083 for the Root Mean Square Error of Approximation. This confirmed the factorial structure of the Japanese version. The IRT analysis, however, revealed that the scale system needed refinement to facilitate appropriate differentiation between each response option.
Conclusions: This study provided preliminary evidence that the Japanese version of ASCOT-SCT4 is valid. As a result, the Japanese version was finalized and approved by the instrument developer.