In response to the shift from a system-centred care model to a person-centred support model, the Supports Intensity Scale (SIS) has been developed as an instrument to assess the support needs of persons with intellectual disabilities. The instrument is used as a tool for constructing individual support plans, as well as a tool for resource allocation. The aim of the present study was to evaluate the usefulness of the SIS for persons with other than intellectual disabilities. Therefore, the psychometric properties of the SIS were investigated in a sample of 1303 persons with other than intellectual disabilities. Confirmatory factor analysis failed to support the originally proposed six-factor model within this sample. However, an explorative examination of the underlying structure resulted in a shortened version of the SIS, including four subscales and 22 items. Further analyses revealed satisfying results for reliability, construct validity, and criterion validity of the shortened assessment tool (SIS-NID). (Contains 4 tables.)