The ability-achievement discrepancy: Does it contribute to an understanding of learning disabilities?

Federal legislation of the 1960s and 1970s extending educational services t o learning disabled children contained a criterion requiring a severe discr epancy between an child's ability and achievement. Following a discussion o f the historical context related to this decision, research related to disc repancy is reviewed rising reading disabilities or dyslexia as the prototyp e. Topics examined include the relationship of IQ to various factors, inclu ding underlying cognitive weaknesses; varying IQ levels; stability of diagn osis; heterogeneity of the diagnostic category; genetic and neuro imaging f indings; and appropriate standards of comparison. Research on the practical application of the discrepancy model is also reviewed In general there is little evidence to support its continued rise Three proposed alternatives a re considered and a possible model is offered that incorporates findings fr om research on diagnosis and intervention.