Misconceptions in Van den Broeck's representation of misconceptions about learning disability research

The methods and conclusions of Van den Broeck (in this issue) are evaluated from two perspectives: (a) statistical considerations and (b) theoretical models of IQ and achievement, specifically reading achievement. We consider the statistical model proposed by Van den Broeck for the regression-based discrepancy model (RDM) to be either irrelevant or conceptually inconsistent with current models of IQ and achievement. The resulting simulation produced exemplar cases that are not realistic in terms of practice. The theoretical representations of IQ and achievement were, in our understanding, inconsistent with contemporary models of either. We suggest that acceptable models support the use of the RDM as it has been proposed by us and by others as one component of the determination of the presence or absence of a learning disability.