Abstract
In response to a debate concerning effectiveness of alternative data handling methods in the hands of experts, the exploratory research reported here was conducted. Experts worked individually except for the SPC expert who was assisted by another expert. Two equal interval graphing experts, two standard behavior or celeration charting experts, and one team of SPC experts were presented with four sets of data that they graphed one point at a time. Their task was to plot, analyze, and identify the location of an intervention within each data set. A total of N = 8 series were plotted and analyzed by each analyst. Average percent of interventions correctly identified by equal interval, celeration, and SPC chartists were respectively, 63%, 32%, and 25%. Rank order of mean hours spent on the exercises was from fewest to most hours, celeration chartists, equal interval chartists, and charting SPC charting team. Regardless of method used, poorer quality baseline data in data series resulted in poorer performances among chartists. Implications are discussed in terms of future research into charting behavior and practical consequences of establishing or failing to establish “good” baseline control prior to introducing interventions in the OBM tradition.