A Study into the Comprehension of Euler Diagrams

We describe an empirical investigation into some of the layout criteria that may facilitate the comprehension of Euler diagrams. The three criteria under investigation were: smoothness, zone area equality and edge closeness. Subjects were asked to interpret diagrams that had good and bad levels of each criterion. The goal of this research is an initial step into using empirical evidence to support decisions concerning the metrics used for automated layout of Euler diagrams. Results for this investigation indicate that, within the parameters of the study, all three criteria are important for understanding Euler diagrams and we have a preliminary indication of the ordering of importance for these criteria.