Are All IQ Scores Created Equal? The Differential Costs of IQ Cutoff Scores for At‐Risk Children

Abstract

ABSTRACT— The IQ cutoff score of 70 used for the diagnosis of mental retardation has repercussions throughout America, influencing educational, social, and legal decision making. Because of the Flynn effect and changing IQ norms, however, IQ scores are rising and falling over time, independent of actual cognitive gains or losses. These fluctuations, combined with the use of the cutoff score, result in substantial misallocations of financial, educational, and social resources for children of all IQ levels but especially for those at risk for academic failure. Such far‐reaching and grave implications call into question the use of IQ cutoff scores in educational and legal policies and underscore the importance for researchers to collect data in real‐world settings to understand and appreciate the issues that surround the application of developmental theory.