Psychometric Evaluation of an Australian Version of the Vocational Index for Adults with Autism

Abstract

Background: Autistic individuals are underrepresented in employment and postsecondary education. Research is hampered by a lack of psychometrically valid instruments that can be used to assess the vocational activities of autistic people. This study examined the psychometric properties of an Australian modified version of the Vocational Index for Adults with Autism (M-VIAA), an assessment of vocational independence.

Methods: Participants were 105 autistic and 106 nonautistic young adults aged 17-26 years recruited from the longitudinal Study of Australian School Leavers with Autism. We examined psychometric properties of the M-VIAA by (1) comparing scores between autistic and nonautistic participants, (2) examining convergent validity with daily living skills, and (3) divergent validity with autistic traits. We explored change over time by comparing baseline and 24-month follow-up scores in autistic participants.

Results: We found vocational independence to be significantly higher in nonautistic participants compared with autistic participants. We did not find a significant relationship between daily living skills and the M-VIAA. There was a small but significant relationship between the M-VIAA and autistic traits. Scores on the M-VIAA remained stable over time for a subsample of autistic participants.

Conclusions: The present study provides preliminary support for the M-VIAA with some limitations. Support for construct validity was mixed with support for concurrent and discriminant, but not convergent validity. We suggest that the M-VIAA may not capture the full complexity of vocational challenges faced by autistic people. Future research should build on the structure of the VIAA while ensuring applicability across cultures and contexts, as well as ensuring the richness of vocational activities of autistic people is captured.

Lay summary: Why was this study done?: Despite the urgent need to improve employment and other vocational outcomes of autistic people, there are few instruments that measure the range of vocational independence demonstrated by these individuals. The Vocational Index for Adults with Autism (VIAA) is an instrument that identifies the common vocational activities that autistic people engage in following high school. There is a need, however, for researchers to examine the usefulness of the instrument and its applicability in countries outside the United States.What was the purpose of this study?: The goal of this study was to evaluate a modified version of the VIAA (M-VIAA) in a group of autistic people from Australia.What did the researchers do?: We examined responses to the M-VIAA in 211 autistic and nonautistic young adults. We compared the M-VIAA with participant's daily living skills and level of autistic traits, as well as any change in scores over time.What were the results of the study?: Vocational independence was higher in nonautistic participants than in autistic participants. Vocational independence was not related to daily living skills; however, it was related to autistic traits. Over 2 years, scores on the M-VIAA did not change a lot for the autistic participants.What do these findings add to what was already known?: Our study provides some initial support for the M-VIAA in a non-US-based population. However, we also identified that the instrument may not represent the full range of challenges nor the richness of vocational activities experienced by autistic individuals in postsecondary vocational settings.What are potential weaknesses in the study?: The M-VIAA provides limited information about the richness of postsecondary vocational and education activities that autistic individuals may be engaged in. Because few individuals reported having an intellectual disability, we are unable to say how our results might apply to these individuals. Because we modified the instrument for use in Australia, our results may not apply to different countries or to the original version of the instrument.How will these findings help autistic adults now or in the future?: Our study provides preliminary support for the Australian version of the VIAA but suggests that it could be improved to better reflect the richness and range of vocational challenges experienced by autistic people. Our findings therefore identify areas for improvement for assessing the vocational activities and independence of autistic people.

Keywords: autism; autistic adults; employment; survey development and psychometrics; vocational independence.