Abstract

Applied research concerning persons with severe/profound and multiple disabilities is often based on single-case designs. The outcome of this research is usually displayed in a graphic format and the visual inspection of the graph is considered the first evaluation strategy. Statistical analysis of the data should possibly follow as a complementary strategy. Different situations can emerge from these two assessments. This paper examines situations in which statistical significance and a visual perception of change in the graphic display of the data are still insufficient to bring about a judgment of clinical significance. Possible discrepancies concerning the judgment of clinical significance are also pointed out. A supplementary evaluation (i.e., social validation assessment) is advised to overcome equivocal situations in which no conclusive judgment can be reached.