Are Type, Frequency, and Daily Time Equally Valid Estimators of Support Needs in Children With Intellectual Disability? A Multitrait–Multimethod Analysis of the Supports Intensity Scale for Children (SIS-C)

Abstract

Support needs represent the intensity of support required by a person with a disability in order to take part in the activities related to normative human functioning. The Supports Intensity Scale for Children (SIS-C) is possibly the most promising tool for assessing and designing individualized support programs in children with intellectual disability. The SIS-C measures support needs across 61 activities, each one assessed along three methods: type of support, frequency, and daily time during which support is to be given. We investigated the impact of method effects in the SIS-C through a bifactor approach to the analysis of multitrait-multimethod matrices. The results suggest that neither intensity nor frequency scales produced method effects that significantly distorted the measurement of support needs. However, the daily support time method had substantial undesirable effects on five of the seven subscales of support needs. Considerations about support needs assessment and future modifications of the scale are discussed.

Assessing support needs in children with intellectual disability and motor impairments: measurement invariance and group differences

“…Verdugo et al 2017) have suggested that it is possible that the response categories need to be revised to reflect shorter increments of time or even transformed into continuous open-ended scales. One interpretation of this result may refer to the content of the items.…”

“…Several studies support the validity of the SIS-C for assessing support needs in children with ID Verdugo et al 2017;Shogren et al 2017b); however, this result has not been replicated in children with IMD. To provide evidence of validity, the first research question asked whether the measurement of support needs varies between groups.…”

“…The analysis of model 2 was performed from a multitrait-multimethod (MTMM) approach, as used in Seo et al (2016) and Verdugo et al (2017), where seven dimensions of support needs and three method factors were specified. Each method factor was measured by the parcels referring to the method used (e.g.…”

“…The scale used was the SIS-C ( Thompson et al 2016) adapted to Spanish (Verdugo et al 2016;Verdugo et al 2017). It aims to assess the extraordinary support that children or adolescents (aged 5 to 16 years) with ID, in comparison with their peers without disabilities, need to participate successfully in different activities of their daily lives.…”

Examining measurement invariance and differences across groups in the support needs of children with and without intellectual disability

“…However, given that in the SIS and SIS‐C each item is rated according to three measurement methods (i.e., type, frequency and daily support time), recent studies on this topic have analysed the relative contributions of the support needs construct and the method factors in the observed support needs in adults and children with intellectual disability. These studies have shown the influence of the method factors that should not be neglected when studying the support needs construct in children and adults with intellectual disability (Seo, Shogren, Little, Thompson, & Wehmeyer, ; Verdugo, Arias, & Guillén, ).…”