In part, this is because many confuse the diverse types of research. The purpose of this brief essay is to articulate a way of looking at research studies and bodies of research that clearly delineates different types of research and the very different implications for practice. This trichotomy of research will serve as a framework for determining what research relates directly to validated practice. Although there is some overlap between categories, most empirical studies in the field of learning disabilities seem to fit one of the three.
Descriptive research can utilize either qualitative or quantitative methodologies.
These studies can be very useful for theory building, for helping shape interventions, and for helping understand the target or focus of an intervention. For example, descriptive research comparing the actual performance of proficient readers with the performance of children with learning disabilities served as a starting point for highly effective interventions in the areas of reading comprehension and expressive writing. Descriptive studies can also help us understand common implementation problems and other pressing problems in current practice. However, despite the rich insights they often provide, they can not serve as evidence of effectiveness. These studies are the building blocks of scientific knowledge about teaching and learning.