Are Standard Scores Higher on the New Vineland?

Background: Adaptive functioning is typically defined as how well individuals function in everyday life including functional communication, social skills, self-helps skills, and community skills. Assessment of adaptive behaviour is an integral aspect of the diagnosis of intellectual disability (together with cognitive level) and is very useful in assessments of children with autism as well (Filipek et al., 1999; Miriam Foundation, 2008; Perry et al., 2002).  The Vineland Adaptive Behavior Scales (VABS; Sparrow, Balla, & Cicchetti, 1984) have been widely used as a developmentally-referenced adaptive behaviour measure since the first edition was published in 1984. The Vineland-II was published in 2005 (Sparrow, Cicchetti, & Balla, 2005).  The second edition retained the essential structure of the original with domains of Communication, Daily Living Skills, Socialization, and Motor Skills, but added some items, changed the basal and ceiling procedures, and changed the scoring somewhat. Clinical experience and anecdotal reports suggest that the new Vineland-II is resulting in higher standard scores than it should, which may have implications for clinical practice as well as the interpretation of research results.

Objectives: The purpose of this study was to investigate empirically the hypothesis that the Vineland-II is resulting in higher standard scores than would be anticipated as compared to VABS scores. 

Methods: While administering the Vineland-II for clinical purposes in a sample of children with autism, a ceiling of 6 rather than 4 is used and several additional questions are included which address questions not directly asked by the Vineland-II, but included on the VABS.  Then scores can be derived for the original VABS as if it had been administered and the two sets of scores compared.  Approximately 50 children have been assessed to date and the final sample is expected to be approximately 75.  Children will be diagnosed with autism or PDD-NOS and range in age from 24 to 84 months. 

Results: It is expected that raw scores and age equivalents scores will be highly correlated across the two measures but that standard scores will be less highly correlated.  It is hypothesized that the standard scores from the Vineland-II will be significantly higher than those from the VABS.  Further, the interrelationship of age equivalent and standard scores from the two versions will be explored in relation to cognitive level and severity of autism.

Conclusions: As a frequently used measure of adaptive behaviour, and considering the importance of adaptive functioning in diagnosis and treatment planning, this topic is of clinical importance.  It will provide invaluable information for the interpretation of Vineland-II results in low to moderate functioning children with autism, which may have additional implications for funding and resource allocation.