Use Case Diagrams for Mobile and Multi-channel Information Systems: Experimental Comparison of Colour and Icon Annotations

In mobile information systems, it may be more important to capture where a user is supposed to perform an activity, as well as what type of device is going to be used, than what is the case for traditional, stationary information systems. Yet, mainstream diagram notations like use case diagrams seldom capture such information. In previous papers we have proposed some adaptations to use case diagrams to be able to include location and equipment requirements, but these adaptations have not been evaluated experimentally. This paper reports on a student experiment comparing two different notations, one using colour and the other using symbolic icons. The experiment also includes a task where the models contained both location and equipment information at the same time. In that case, one alternative used colour for locations and icons for equipment, while the other used icons both for colour and equipment. The results showed no significant difference between the two treatment groups, neither in the quality of answers to the experimental tasks, the time needed to perform the tasks, nor in their opinions given in post-task questionnaires about the notations they were exposed to.