Operational Definitions and Learning Disabilities: An Overview

Abstract

In 1981, the National Joint Committee for Learning Disabilities (NJCLD) adopted the following definition: Learning disabilities is a generic term that refers to a heterogeneous group of disorders manifested by significant difficulties in the acquisition and use of listening, speaking, reading, writing, reasoning, or mathematical abilities. These disorders are intrinsic to the individual and are presumed to be due to central nervous system dysfunction. Even though a learning disability may occur concomitantly with other handicapping conditions (e.g., sensory impairment, mental retardation, social, or emotional disturbance) or environmental influences (e.g., cultural differences, insufficient/inappropriate instruction, psychogenic factors), it is not the direct result of these conditions or influences. (Hammill, Leigh, McNutt, & Larsen, 1981, p. 336) This definition has been evaluated positively compared to others (e.g., Interagency Committee on Learning Disabilities, 1987; U.S.O.E., 1977; e.g., see Hammill, 1990; Silver, 1988). However, it is not an operational definition, because it does not specify the operations or procedures by which the construct of learning disabilities can be recognized and measured. For example, it is unlikely that current studies on learning disabilities would be published in refereed research journals if their subject sample description relied solely on the NJCLD definition. Therefore, if we are to enhance our understanding of learning disabilities, serious consideration must be given to the selection of parameters that go into an operational definition. It is in this spirit that this special issue of the Learning Disability Quarterly was developed. In this opening discussion, I seek to distill some ideas that unify what otherwise might appear to be a collection of unintegrated articles. The reader should remember, however, that each article is written from the authors' own research perspective. I deliberately solicited articles of diverse research perspectives to allow a number of issues to be considered. For example, in the first article Kavale, Forness, and Lorsbach discuss the limitations of operational definitions, whereas the article by Stanovich focuses on the irrelevancy of IQ. Likewise, Hynd, Marshall, and Gonzalez emphasize the relevance of studies originating from neuropsychology, Reynolds' article targets psychometric models, while Bryan considers primarily social cognition. No doubt, to integrate these diverse perspectives will be no small feat. The purpose of this special issue, however, is not to show or seek unanimity among the contributors on how to operationalize learning disabilities. Rather, the focus is on the commonality of conceptual issues that emerges in our attempts to operationalize learning disabilities.