More Ups and Downs of Subtest Analysis: Criterion Validity of the DAS with an Unselected Cohort

Abstract

This research evaluated the criterion-related validity of unusual subtest profiles from the Differential Ability Scales (Elliott, 1990). Three methods were used to identify unusual profiles: multivariate-nomothetic, univariate-nomothetic, and univariate-ipsative prevalence rates ≤ 5%. Participants were a large cohort (N = 1,200) stratified, within age levels, in proportion to U.S. Census data on demography (e.g., race, gender, parents' educational levels). From this cohort, children with unusual profiles were identified (n = 60) and matched to controls (n = 60) by the characteristics listed and overall IQs. The two groups were compared across a variety of external criteria: (a) propensity for placement in special education, (b) three norm-referenced measures of achievement, and (c) six behavioral indices evaluated through standardized teacher ratings. Results showed no group differences across all criteria, regardless of the method used to identify unusual subtest profiles. Findings are discussed in the context of the criterion validity of specific ability constructs.

Additional information

Notes on contributors

Joseph J. Glutting

Joseph Glutting, PhD, is Professor of Educational Studies with specialization in school psychology, at the University of Delaware. His research includes intellectual assessment, multivariate strategies for typology development, and the interpretation of ability profiles.

Timothy R. Konold

Timothy R. Konold is Assistant Professor in the Department of Leadership, Foundations, and Policy, Curry School of Education, University of Virginia. His research interests span applied psychometrics, test development, and classification systems.

Paul A. McDermott

Paul A. McDermott is Professor of Policy Research, Evaluation, and Measurement and Chair of the Division of Psychology in Education at the Graduate School of Education of the University of Pennsylvania. He is Director of the PhD Program in School, Community, and Clinical Child Psychology. His research includes assessment of youth psychopathology and learning styles, adult substance abuse, and multivariate strategies for typology development.

Alisa J. Snelbaker

Alisa J. Snelbaker is a graduate student in the MS+30 program in School Psychology at the University of Delaware. Her research interest include applied assessment issues, test development, and school consultation models.

Marley W. Watkins

Marley W. Watkins, PhD, is Associate Professor of School Psychology at Pennsylvania State University. He is a Diplomate in School Psychology, American Board of Professional Psychology, and his research interests included diagnostic assessment, the development of microcomputer interpretation programs, and computer-assisted instruction.