Further Thoughts on Aptitude/ Achievement Discrepancy

Summary We react to the recent commentaries on discrepancy definitions of reading disability by Frederickson and Reason (1995), Ashton (1996), and Solity (1996). We clarify many of the arguments in our earlier writings on the subject (Stanovich, 1991; 1994; Stanovich and Stanovich, 1996). Over a decade ago, when we started writing on this issue, there was little evidence indicating that poor readers of high and low IQ differed importantly in the primary processing mechanisms that were the cause of their reading failure. A further decade's worth of empirical work on this issue has still failed to produce such evidence. In the research community, the idea that aptitude/ achievement discrepancy tells us anything important about the processing mechanisms underlying reading difficulties is becoming untenable. The progress in understanding reading and reading failure that has been made is virtually orthogonal to the issue of reading/IQ discrepancy (see Shaywitz, 1996).