Improving graphical information system model use with elision and connecting lines

Graphical information system (IS) models are used to specify and design IS from several perspectives. Due to the growing size and complexity of modern information systems, critical design information is often distributed via multiple diagrams. This slows search performance and results in reading errors that later cause omissions and inconsistencies in the final designs. We study the impact of large screens and the two promising visual integration techniques of elision and connecting lines that can decrease the designers' cognitive efforts to read diagrams. We conduct a laboratory experiment using 84 computer science students to investigate the impact of these techniques on the accuracy of the subjects' search and recall with entity-relationship diagrams and data flow diagrams. The search tasks involve both vertical and horizontal searches on a moderately complex IS model that consists of multiple diagrams. We also examine the subjects' spatial visualization abilities as a possible covariant for observed search performance. These visual integration techniques significantly reduced errors in both the search and the recall of diagrams, especially with respect to individuals with low spatial visualization ability.