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Autism spectrum disorder (ASD) is characterized in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; APA, 2013) by deficits in social communication and the presence of restricted and repetitive behaviors and interests (RRBIs). Despite the mandatory requirement of both categories of impairment for a diagnosis of ASD, research regarding RRBIs is minimal, when compared to that of social impairments. The Repetitive Behavior Scale-Revised (RBS-R; Bodfish et al., 2000) is a rating scale designed to capture the broad range and scope of RRBIs in individuals with ASD. Among the few RRBI measures available, researchers have used the RBS-R as an outcome measure in several intervention studies. Despite its relative popularity, RBS-R validity research has yet to yield a consensus regarding the tool's factor structure. Such consensus is needed to clarify the number of subscales and their constructs, as well as establish item-to-subscale assignments. Previous factor analytic studies (Bishop et al., 2013; Bodfish et al., 2000; Lam & Aman, 2007; Mirenda et al., 2010; Russell et al., 2019; Hooker et al., 2019; Sturm et al., 2022), have used caregiver ratings on the RBS-R in ASD samples, yielding a variety of factor solutions (i.e., four-, five-, or six-factor solutions). Though variable, analyses have produced more support for a five-factor solution among caregiver ratings of repetitive behavior (Bishop et al., 2013; Hooker et al. 2019; Lam & Aman, 2007; Mirenda et al., 2010; Sturm et al., 2022). Additional factor analytic studies conducted using non-English versions of the RBS-R in other cultural contexts (Georgiades et al., 2010; He et al., 2019; Kastel et al., 2020), using caregiver ratings of ASD samples also yielded inconsistencies in the number of factors present (i.e., two, four, and six factors). Only one published factor analytic study involved the use of school staff ratings of the RBS-R in an ASD sample. This study (Martinez-Gonzalez & Piqueras, 2017) utilized the Spanish version of the instrument in Spain and authors;retained a six-factor solution. This has left questions about the range of factor solutions examined across studies, as well as possible differences in factor structure due to rater type. The lack of consensus, in addition to the lack of school raters, warrants independent factor analyses to determine the most appropriate, valid factor structure of the RBS-R among school staff raters. The present dissertation involves two independent studies. Study one utilized an exploratory factor analysis (EFA) of the RBS-R items with an ASD sample (N = 234), rated by special education staff. The EFA resulted in a five-factor solution that demonstrated some similarities to existing factor models, though presented clear differences not previously observed in the literature. Study two involved applying confirmatory factor analysis (CFA) in a second independent ASD validation sample (N = 233) from the same agency used in study one. CFA procedures were used to test the fit of the RBS-R factor solution retained from study one across five fit indices and to compare the fit of that model to others available in the literature. CFA results suggested that the five-factor model from study one adequately fit the sample data. AIC and BIC indices indicated that the study one model was the best-fitting model compared to the existing models. Findings underscore the possibility that the current structure of the RBS-R may not be most viable, when using school staff ratings. Findings also suggest the presence of a new, unique factor resulting from dividing items from the original RBS-R self-injurious behavior factor. Further, findings leave room for future studies to continue to consider the factor structure and fit of models of the RBS-R based on school staff ratings in samples of those with ASD. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtmlTest.] |
