In the field of special education there is a dearth of group experimental studies that establish evidence-based practice. The effort to establish evidence-based practice has been associated with emphasizing experiments by using randomized controlled trial with large numbers of participants who are randomly assigned to a treatment. However, single-case design (SCD) research can play a vital role in filling the gaps and determining educational interventions that establish evidence-based practices in the special education. The goal of this present paper is to provide an overview of SCD methods and how these methods can establish evidence-based practices in special education. The author shares the critical features of SCD, including the way steady state strategy and baseline logic works in common designs. Internal and external validity are also addressed. Finally, this paper communicates why a visual analysis of data is considered conservative in SCD rather than tests of statistical significance.