Learning Disability Research: How Far Have We Progressed?

This article presents an analysis of the 229 research reports which have appeared in two major learning disability journals since 1978. Findings indicate that (1) the vast majority of these studies are quasi-experimental in nature; (2) control of extraneous variables (e.g., intelligence) was not appropriately demonstrated in many studies; (3) comparability between experimental and control groups was not adequately established in numerous reports; (4) fewer than half of the studies utilized subjects classified as learning disabled; (5) in more than two-fifths of the studies involving learning disabled subjects, the criteria for such classification were not provided; (6) studies which did operationally define learning disabilities utilized a wide range of criteria. The ethical limitations of conducting experimental learning disability research are discussed and suggestions for enhancing such research are offered. Finally, the importance of focusing research efforts on homogeneous populations (e.g., the severely learning disabled) is illustrated.