Aptitude-Achievement Discrepancy Scores: Accuracy in Analysis Ignored

Abstract

The results of the study I reported in this issue indicated that practitioners have difficulty analyzing discrepancy scores accurately, thus calling into question the reliability of decisions based on such analyses. My suggestions for dealing with practitioners' problems in understanding measurement were dismissed as not worth doing by Barnett and Macmann who argued that discrepancy scores lack sufficient reliability and validity to be used for decisions in the first place. While it is true that technical solutions to the problems of discrepancy analysis will not solve the problem of getting help for all children who need it, it is premature to conclude that we should cease such efforts or replace current methods of identifying children for special services with an alternative service delivery method of unknown reliability and usefulness. Ways need to be found to implement and evaluate promising alternatives without disrupting the entire system. A sound understanding of measurement would appear to be needed no matter which assessment strategy is adopted.