Collection of interobserver agreement data and reporting the results with summary statistics are standard practices in single-case research. An alternative to summary statistics is plotting the second observer's data on the same graph as the primary observer. In this study, we evaluated whether plotting the second observer's data differentially influenced the judgments about functional relations for A-B-A-B designs. Participants were graduate students and experts. Results suggested that (a) experts made more accurate judgments than graduate students, (b) raters made more accurate judgments for graphs with 1 rather than 2 primary data paths, and (c) raters were not influenced differentially in their judgments of functional relations by the presence or absence of the second observer's plotted data. In addition to standard hypothesis testing, equivalence testing was performed and showed accuracy of judgments was equivalent for graphs with and without the second observers' data being added.