The critical issue in special education today is no longer the assurance of access, but rather, the assurance of effectiveness. Determining which practices and interventions are most effective and efficient for ensuring optimal student achievement is a fundamental concern of special education teachers in this era of accountability. In this discussion I examine three designs commonly used in special education research (experimental research designs, meta-analyses, and narrative research syntheses) and their utility and appropriateness for determining the efficacy of classroom practices and interventions. (Contains 1 table.)