The problems of definition and differentiation and the need for a classification schema.

Abstract

From both a theoretical and practical perspective, the majority of respondents to the future survey recognized the as yet unmet need to develop valid procedures for differential diagnosis and subtyping of learning disabilities. The foundation for developing such procedures was seen as requiring agreement about the definition of LD and appropriate ways to operationalize the definition. There was, however, a major split among the respondents regarding how LD should be defined. Some wanted to keep the definition tied to learning problems stemming from central nervous system dysfunctions; others wanted to ignore cause and broaden the field by defining as LD any learning problem that is not readily understood. These contrasting views about definition were then reflected in the controversy among respondents about operational criteria, e.g., the appropriateness and feasibility of identifying LD based on a severe discrepancy between aptitude and achievement. Another concern was raised in connection with the matter of identifying LD subtypes, i.e., some respondents viewed such efforts as confounded by the lack of satisfactory procedures for differentiating LD from learning problems caused by other factors. In general, then, the survey responses underscore the controversy and widespread frustration over definition and differentiation and suggest that the LD field's future integrity is very much dependent on successfully dealing with these problems. It is time, we think, for the field to take a step back from narrow debates over definition and deal with the fundamental problem of developing a comprehensive classification scheme, i.e., one in which LD is differentiated from other categories of learning problems and subtypes are conceived within each category. The following paper on definition and subtypes focuses briefly on the nature of the definition and differentiation problems, the importance of placing and keeping LD in perspective vis à vis other learning problems, and ideas related to future development of a LD classification schema. (We should note that, in the course of recent events, the preparation of this paper for the series fell to us.)