The Power of One: Using Single-Case Experimental Designs to Inform Evidence-Based Practice

The evidence-based practice movements continue to impact upon the research paradigms across the fields of health care, psychology, and education. With the difficulties associated with conducting randomised control trials (RCTs) in applied settings together with the limitations of group designs in evaluating changes for individual participants, it is argued that single-case experimental designs (SCEDs) are an effective way to provide scientific evidence on the effectiveness of interventions in a range of disciplines. In this context, SCEDs are defined and described to assist in the implementation and interpretation of studies using these methods. Research design strategies that can be used with as few as one participant to reliably document changes in pehaviour or wellbeing as a function of environrhental conditions (interventions or treatments) are explored. A discussion of how a synthesis of data from SCEDs can inform evidence-based practice and directions for further research in a relevant field is also provided.