ACCURACY IN ANALYSIS OF DISCREPANCY SCORES - A NATIONWIDE STUDY OF SCHOOL-PSYCHOLOGISTS

This study investigated whether psychologists possess the psychometric knowledge necessary to evaluate discrepancies within an individual's test performance with sufficient accuracy to ensure reliable decision making. Two-thirds of a randomly drawn nationwide sample of nationally certified school psychologists responded to a questionnaire that asked them to evaluate four sets of achievement-ability test scores, rate the usefulness of various test measures for different purposes, and provide information on how achievement-ability discrepancies, a criterion for learning disability (LD) classification, were being identified in their settings. Only 8.7% of 287 respondents were able to correctly evaluate whether four sets of ability-achievement scores reflected chance measurement differences or reliable, non-chance differences. Increased accuracy was associated with working in a state recommending regression analysis and providing simplified operational procedures, in the form of tables, for evaluating test score discrepancies.