Single-subject experimental designs – also referred to as within-subject or single case experimental designs – are among the most prevalent designs used in CSD treatment research. These designs provide a framework for a quantitative, scientifically rigorous approach where each participant provides his or her own experimental control. Show
An Overview of Single-Subject Experimental DesignWhat is Single-Subject Design?
What is the Role of Single-Subject Design?
Basic Features and Components of Single-Subject Experimental DesignsDefining Features
See Kratochwill, et al. (2010) Structure and Phases of the Design
Basic Components
See Horner, et al. (2005) Common MisconceptionsSingle-Subject Experimental Designs versus Case Studies
Single-subject studies should not be confused with case studies or other non-experimental designs.
Other Single-Subject Myths
Further Reading: Components of Single-Subject DesignsHorner, R. H. , Carr, E. G. , Halle, J. , McGee, G. , Odom, S. , & Wolery, M. (2005). The use of single subject research to identify evidence-based practice in special education. Exceptional Children, 71,165–179. [Article] Kratochwill, T. R., Hitchcock, J., Horner, R. H., Levin, J. R., Odom, S. L., Rindskopf, D. M. & Shadish, W. R. (2010). Single-case designs technical documentation. From the What Works Clearinghouse. http://ies.ed.gov/ncee/wwc/documentsum.aspx?sid=229 McReynolds, L. V. & Thompson, C. K. (1986). Flexibility of single-subject experimental designs. Part I: review of the basics of single-subject designs. Journal of Speech and Hearing Disorders, 51, 194-203. [Article] [PubMed] Further Reading: Single-Subject Design TextbooksKazdin, A. E. (2011). Single-case research designs: Methods for clinical and applied settings. Oxford University Press. McReynolds, L. V. & Kearns, K. (1983). Single-subject experimental designs in communicative disorders. Baltimore: University Park Press. Further Reading: Foundational ArticlesBaer, D. M., Wolf, M. M. & Risley, T. R. (1968). Some current dimensions of applied behavior analysis. Journal of applied behavior analysis, 1, 91-97. [Article] [PubMed] Baer, D. M., Wolf, M. M. & Risley, T. R. (1987). Some still-current dimensions of applied behavior analysis. Journal of Applied Behavior Analysis, 20, 313-327. [Article] [PubMed] What are the advantages of using single case designs?Single cases allow researchers to investigate phenomena in-depth to provide rich description and understanding. A single case may also be used as a pilot study for a research project in which several cases are required, especially where the study is of an exploratory nature.
How many baseline points should a single system design include?You probably should take at least two more baseline measures, but three or four additional mea- sures may be necessary to see a pattern emerge.
What components are necessary for a single case research study to be considered quality?Quality and rigor evaluations should at minimum include evaluations of (1) sufficient potential demonstrations of effect (at least three at three different points in time), (2) reliability of dependent variables, and (3) measurement of fidelity of independent variable implementation across all conditions in the design.
What is the purpose of repeated measurements in the intervention phase of the study?During the base- line phase, repeated measurements of the dependent variable are taken or recon- structed. These measures reflect the status of the client (or agency or community) on the dependent variable prior to the intervention.
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