We used a prepublication version of the Supports Intensity Scale (SIS), the Adaptive Behavior Scale-Residential and Community, and the Inventory for Client and Agency Planning to examine the relationship between support needs and adaptive behavior for 80 people with intellectual disabilities. Dimensionality of the SIS Support Needs Scale (Section 1) was examined in reference to the three areas of conceptual, social, and practical skills reported by the American Association on Mental Retardation as comprising the adaptive behavior construct. Factor analysis of the adaptive behavior subscales and SIS Support Need Scale offered support for measurement of a common underlying construct. When considered in terms of the three adaptive behavior skill areas, this construct related predominantly to conceptual skills.

The results provide support for the use of SNAP as a support needs instrument.

Numerous researchers have reported a high incidence of additional disabilities coexisting with intellectual disabilities. Although an intuitive link can be made between the existence of multiple disabilities and greater need for support, little has been reported about this relationship. Using measures of adaptive functioning and support needs, we examined the extent to which adaptive and challenging behaviors and consequent support needs (including medical) were impacted by the presence and severity of additional disabilities for individuals with intellectual disabilities. Results show that adaptive behaviors and support needs were meaningfully related to the number and severity of additional disabilities present, whereas this was not so for challenging behaviors. Findings are discussed in terms of contemporary models of disability and functioning.

Our results suggest that support measures such as SNAP may significantly overestimate support needs when raters know the assessment is being used for funding purposes.

The International Classification of Functioning, Disability and Health (ICF) assumes a biopsychosocial basis for disability and provides a framework for understanding how environmental factors contribute to the experience of disability. To determine the utility of prevalent disability assessment instruments, the authors examined the extent to which a range of such instruments addressed the impact of environmental factors on the individual and whether the instruments designed for different disability groups focused differentially on the environment. Items from 20 widely used disability assessment instruments were linked to the five chapters of the ICF environment component using standardized classification rules. Nineteen of the 20 instruments reviewed measured the environment to varying degrees. It was determined that environmental factors from the Natural Environment and Attitudes chapters were not well accommodated by the majority of instruments. Instruments developed for people with intellectual disabilities had the greatest environmental coverage. Only one instrument provided a relatively comprehensive and economical account of environmental barriers. The authors conclude that ICF classification of environmental factors provides a valuable resource for evaluating the environmental content of existing disability-related instruments, and that it may also provide a useful framework for revising instruments in use and for developing future disability assessment instruments.