This article takes a further look at the percentage of data points exceeding the median (PEM) analysis method for single-case research data, first presented in this journal by Hsen-Hsing Ma. Ma examined the relationship between PEM and the established percentage of nonoverlapping data (PND) and then applied PEM in a meta-analysis of 61 data sets,…

Previous visual analysis research reported that the overall agreement between visual analysis and statistical analysis was poor. In response, some researchers suggested the use of celeration lines to improve the accuracy and reliability of visual analysis. However, subsequent research reported little or no improvement in accuracy with such lines.…

This study explored some practical issues for single-case researchers who rely on visual analysis of graphed data, but who also may consider supplemental use of promising statistical analysis techniques. The study sought to answer three major questions: (a) What is a typical range of effect sizes from these analytic techniques for data from…