In this article, external factors behind abuse incidents at support facilities for persons with disabilities were investigated. As a method, data analysis of previous studies was conducted to demonstrate that the highest rate of abuse incidents was indicated in cases committed by care workers. The analysis revealed four aspects of the causative factors, namely, 1) care workers require highly specialized expertise to perform their tasks at support facilities that accept persons with various types and level of disabilities, 2) the acquisition status of care workers'expertise often does not agree with the levels the facility administration would expect of their human resources, 3) the number of candidates when recruiting care workers is relatively small, and 4) there is a custom at support facilities to defer employee's "personal" matters until later to prioritize the smooth operation of the facility. Based on these elements, the cycle of abuse incidents at support facilities for persons with disabilities was examined. In addition, this study identified underlying problems in the currently promoted decision-making support program.
 Author's abstract