Abstract
The present study investigated the hypothesis that the higher prevalence of reading disability (RD) often observed among boys is partly an artifact of gender bias in the prediction of reading from IQ. The relevant regression statistics derived from a sample of more than 900 children revealed a statistically significant intercept bias. Predicted reading scores for boys were systematically overestimated, thereby inflating IQ-reading discrepancies; the converse was found for girls. When defined separately for girls and boys, severe underachievement in reading was found to be equally prevalent in both genders and, furthermore, was associated with qualitatively and quantitatively similar patterns of deficits. Because the bias arose from general differences between boys and girls in reading score distributions (a lower mean and greater variance for boys) rather than from differences in IQ scores, gender bias poses a potential threat not only to traditional IQ-discrepancy definitions but also to post-discrepancy definitions that are based solely on reading score cutoffs.