Reliability and Validity of the Diagnostic Instrument on Adaptive Behaviour: A New Instrument Measuring Adaptive Behaviour in People With Moderate, Severe or Profound Intellectual Disability.

The DIAB was tested in only 73 adults living in 24/7 residential care in the Netherlands, so it may not apply to people with intellectual disability who live independently, receive day care, or are in other countries. The comparison measures SRZ and SMZ are Dutch instruments, and the paper notes they were validated when adaptive behaviour was conceptualised differently. Discriminant validity was not fully supported: DIAB domains correlated strongly with each other and with several SRZ subdomains, so the domain scores may not separate conceptual, practical, and social skills clearly. The study did not test sensitivity to change, so it does not show whether DIAB scores can track progress after therapy or support planning. Informants were required to have worked with the client for at least 3 months, but the paper did not report how long they had worked with the client, so familiarity with the client may vary. Aetiology and ethnicity were not collected, so the sample may not represent all groups with intellectual disability. Participants had to be functioning stably, and severe immobilising conditions, active psychosis or mania, severe visual or hearing impairment, severe uncontrolled epilepsy, and severe motor impairment affecting all four limbs were excluded, so results may not apply to people with those conditions.

Hinke Elisabet Drijver is an author of the DIAB and was employed by care organization 's Heeren Loo; development and initial testing were funded by charity organisations, and ZonMw is listed as funder.

Do not conclude that the DIAB is a validated diagnostic or outcome measure for all people with intellectual disability. It was tested in 73 Dutch adults with moderate to profound intellectual disability, its separate skill areas were not fully distinct, and sensitivity to change was not tested.