ABSTRACT
The classification of disabled learners is a major problem for researchers and practitioners who attempt to understand the cognitive and social difficulties associated with learning problems in children. Recent reviews of the methodology underlying learning-disabilities research (Doehring, 1978; Rourke, 1985; Satz & Fletcher, 1980) have uniformly concluded that many of the interpretive problems characteristic of this area reflect the absence of valid operational criteria for defining different types of learning disabilities. Most studies rely on exclusionary definitions that select disabled learners according to the absence of certain problems (e.g., low intelligence) that potentially explain the learning problem. However, these definitions are poorly operationalized, have rarely been subjected to empirical analysis, and are based primarily on tradition. Hence, selection criteria, and therefore the samples of learning-disabled children, vary from study to study. Discrepant results across studies are attributed in part to this sampling and taxonomic variation.
