Comparison of self-determination of students with disabilities: multivariate and discriminant function analyses.

BACKGROUND: Self-determined behaviour is composed of multiple, interrelated component elements, and yet little empirical study has researched the self-determination components other than choice making and goal setting. Also, few theoretical relationships have been drawn between the component elements of self-determined behaviour and the impact of disability category. Therefore, this study examined profiles of the combination of three self-report measures of component elements of self-determined behaviour (autonomous functioning, problem solving and internal locus of control) between two groups (ID and learning disabilities/emotional disorders). METHOD: We analysed data from 96 middle school and high school students ages 13 through 22 years who completed three self-report instruments of the Autonomy - section 1 of The Arc's Self-determination Scale, the Problem Solving Survey and the Nowicki-Strickland Locus of Control Scale. A multivariate analysis of covariance was conducted to investigate the differences between the two groups after controlling for the developmental effects of age. A discriminant function analysis examined whether membership of the two groups could be predicted from the three component elements. RESULTS: Results showed that each group had different profiles within the combined three component elements of self-determination but groups were not different on any single measure of component elements of self-determined behaviour exclusively. The combination of three variables was useful in confirming the membership of two dichotomous groups. CONCLUSIONS: Score differences on the three component behaviour imply that the two groups have different instructional needs and therefore require differentiated instructional approaches. The three measures of the component elements of self-determined behaviour collectively separate the two groups, suggesting that the component elements should be considered in a combination as opposed to being treated as individual elements in the context of discussing self-determined behaviour.