Synthesis of single-case design research in communication sciences and disorders: Challenges, strategies, and future directions

Abstract

The synthesis of scientific evidence has been undertaken for decades as a key mode of knowledge acquisition and development. With the growing evidence-based practice movement, the statistical aggregation tool of meta-analysis, with its techniques for measuring effect size, has become an integral method for assessing, analyzing, comparing, and quantifying findings from primary research studies. The role of meta-analysis in scientific and clinical decision making is expanding; however, evidence from single-case design research has been largely omitted from such efforts due to a lack of appropriate techniques, subpar methodology, and theoretical divisions. As single-case design research is a common methodology used in the study of low-incidence and heterogeneous populations, practice-based fields such as communication sciences and disorders are in need of methods to aggregate the available research and incorporate it into evidence-based decision making. This article outlines the challenges to synthesis of single-case design research, describes and critiques the available synthesis methods, and offers suggestions for current synthesis efforts and future research directions in communication sciences and disorders.

Source of funding: No source of funding reported.

Keywords:

• Single-case design
• Evidence-based practice
• Meta-analysis
• Effect size
• Synthesis

Acknowledgments

I would like to acknowledge the guidance of Lee McLean and Linda Watson in the preparation of this manuscript.

Declaration of interest: The author reports no conflicts of interest. The author alone is responsible for the content and writing of this article.