Aptitude-Achievement Discrepancy Scores: Accuracy in Analysis Misdirected

Abstract

Measurement issues pervade professional practice and the research by Ross (in this issue) enables an examination of one of the most misinterpreted targets of measurement — discrepancy scores. While analyses of discrepancy scores in educational settings most often involve aptitude-achievement differences, the issues apply to development profiles in general. Despite the widespread use, aptitude-achievement discrepancy scores do not meet standards of reliability and validity for professional decisions. We present arguments within the context of guidelines for test interpretation and the estimation of error. We offer suggestions for training and practice based on collaborative problem solving, the analysis of problem situations, and the evaluation of intervention outcomes.

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Notes on contributors

David W. Barnett

David W. Barnett, PhD, is a Professor of School Psychology at the University of Cincinnati. His research and practice interests include services to preschool children, decision making, and assessment and intervention design.

Gregg M. Macmann

Gregg M. Macmann, PhD, received his doctorate from the University of Cincinnati in 1987. He is currently an Assistant Professor at the University of Iowa. His research interests include assessment for decision making, collaborative consultation, and methodological issues in scale validation.