Single-case design (SCD) is frequently utilized in applied contexts, such as schools or clinics, due to its utility in evaluating individual intervention effects of students. Data collected in SCD are often displayed in a linear graph, which can vary drastically in their construction leading to inconsistencies in rater interpretation. This has led to a need for a standardized format for linear graphs for practitioners and researchers to follow when constructing graphs. The purpose of this study was both to evaluate how well practitioner-created graphs adhered to Standard Assembly (SA) guidelines and to investigate visual analytic differences in graphs generated by practitioners and the same data replotted in adherence to SA guidelines. Practitioner graphs were collected from fourteen practicing school psychologists and evaluated against SA guidelines. Graphs were found to have vast differences in graph characteristics. Twenty-seven participants, faculty members with experience in SCD, were asked to evaluate 32 graphs--16 of which were practitioner created and the other 16 being the same data sets regraphed according to SA standards. Participants were asked to rate the interpretability of each graph and evaluate the magnitude of the intervention effect. Results indicate that there were no significant differences between the practitioner-created graphs and SA graphs in intervention effect estimates, but the SA graphs were rated as significantly more interpretable.