Basic Specialist Disability Accommodation (SDA) housing refers to ‘Existing’ and ‘Legacy’ building types enrolled in the SDA program but constructed prior to the introduction of the National Disability Insurance Scheme (NDIS). In a policy context, the ‘Existing’ building type largely refers to group homes housing up to five residents, while ‘Legacy’ reflects congregate housing with six residents or more. Throughout this report the term Basic SDA is used to collectively describe both Existing and Legacy building types enrolled in the program under the Basic design category.