Interactive usability instrumentation

Usage data logged from user interactions can be extremely valuable for evaluating software usability. However, instrumenting software to collect usage data is a time-intensive task that often requires technical expertise as well as an understanding of the usability issues to be explored. We have developed a new technique for software instrumentation that removes the need for programming. Interactive Usability Instrumentation (IUI) allows usability evaluators to work directly with a system's interface to specify what components and what events should be logged. Evaluators are able to create higher-level abstractions on the events they log and are provided with real-time feedback on how events are logged. As a proof of the IUI concept, we have created the UMARA system, an instrumentation system that is enabled by recent advances in aspect-oriented programming. UMARA allows users to instrument software without the need for additional coding, and provides tools for specification, data collection, and data analysis. We report on the use of UMARA in the instrumentation of two large open-source projects; our experiences show that IUI can substantially simplify the process of log-based usability evaluation.