Data AnalysisThe data were placed in graphs and visually inspected for changes in the trend, slope, and level of the data (Kazdin, 1982). The percentage of non-overlapping data points across phases was also calculated (Scruggs & Mastropieri, 1998); that is, the percentage of points during the intervention phase that exceeded the highest baseline data point. used better language skills?, and (2) In which tape do you think your child/student communicated more effectively? Informal interviews were also completed to determine perceptions of the strengths and weaknesses of the intervention.