According to a revision of Japan's Basic Law for Persons with Disabilities in 2011, Article 17 stipulated the government's obligation to provide early intervention to children with disabilities. However, the concept of family outcomes in early intervention has not really been considered in Japan yet. This article describes the development and validation of the Japanese version of the Family Outcomes Survey Revised (FOS-R). Our goal was to determine whether this survey for assessing how families of children with disabilities are affected by early intervention would be appropriate for use in early intervention in Japan. Both the Japanese version of the FOS-R and an anonymous, self-administered questionnaire about background factors were given to 394 mothers of children who were either currently using or had in the past year used early intervention at an early intervention facility or medical institution. Survey responses were obtained from 335 mothers (response rate of 85.0%). The total number of subjects in the analysis was 301 mothers who answered the Japanese version of the FOS-R completely. To assess content validity, another survey was given to 115 experts involved in supporting children with disabilities and their families. The family outcomes indicator items as well as the helpfulness indicators items showed good psychometric properties. Although the components of the FOS-R worked better as individual subscales than as a single scale, we confirmed that a total score was also psychometrically valid. We also confirmed both content validity and external validity. The Japanese version of the FOS-R appears to be a valid tool for assessing the benefits experienced by families as a result of services received, but further research is needed to determine the nature of practices most likely to lead to positive family outcomes
