While the classification rates for all three analyses were statistically significant, there were a reasonable number of subjects that were misclassified. Examination of the differences between the misclassified subjects and those who were correctly classified yielded useful clinical information. Knowledge about which subjects are more likely to be misclassified may be just as important as knowing how to classify subjects with AE. For example, our data show that in this sample, controls who were younger, with lower IQ scores, and/or from South Africa were more likely to be misclassified as AE. In contrast, AE subjects from the U.S., with higher IQ, were more likely than other AE subjects to be misclassified as controls. It is difficult to disentangle the factors that led to misclassification as some of the factors may be related to country of origin. Children in this study from South Africa are exclusively non-White and non-Hispanic. They also come from more vulnerable, less stimulating environments (Adnams et al., 2007) and are physically smaller (May et al., 2007) than subjects from the U.S. Future studies with different samples will
