Group Experimental and Quasi-Experimental Research Designs for Special Education Intervention Validation

Abstract

The term evidence-based practice remains an important concept within special education research, policy, and practice. Evidence-based practice requires that interventions, strategies, and policies undergo a systematic process of experimentation and replication to demonstrate their effectiveness. The use of experimental or quasi-experimental designs allows researchers to infer causal relationships between a practice and a set of outcomes. While special education researchers and research consumers value experimental and quasi-experimental methods via evidence-based practice, we often overlook the assumptions associated with these designs. The purpose of this chapter is to provide a primer on experimental and quasi-experimental research methods with a specific focus on their use within special education. In the following chapter, we describe (a) the logic of causal inference, (b) experimental and quasi-experimental design options that researchers may deploy, and (c) the strengths and limitations of this class of studies. We draw on examples from the special education literature and highlight key terms throughout the chapter.