Perspective-based Usability Inspection: An Empirical Validation of E cacy

Inspection is a fundamental means of achieving software usability. Past research showed that the current usability inspection techniques were rather ine ective. We developed perspective-based usability inspection, which divides the large variety of usability issues along di erent perspectives and focuses each inspection session on one perspective. We conducted a controlled experiment to study its e ectiveness, using a posttest only control group experimental design, with 24 professionals as subjects. The control group used heuristic evaluation, which is the most popular technique for usability inspection. The experimental design and the results are presented, which show that inspectors applying perspective-based inspection not only found more usability problems related to their assigned perspectives, but also found more overall problems. Perspective-based inspection was shown to be more e ective for the aggregated results of multiple inspectors, nding about 30% more usability problems for 3 inspectors. A management implication of this study is that assigning inspectors more speci c responsibilities leads to higher performance. Internal and external threats to validity are discussed to help better interpret the results and to guide future empirical studies. 1 Usability Inspection Techniques Usability inspection [14] is an important approach to achieving usability. It asks human inspectors to detect usability problems in a user interface design so that they can be corrected to improve usability. It usually requires multiple inspectors, who can either work individually or as a team. Usability inspection di ers from user-based evaluation methods such as usability testing [6] or evaluation in participatory design [24]. In user-based methods usability problems are found through the observation of and interaction with users while they use or comment on an interface. In usability inspection, problems are found through the expertise of the inspectors and the inspection technique they use. Di erent usability inspection techniques have been practiced, including heuristic evaluation, cognitive walkthrough, and formal usability inspection, etc. [20]. Empirical studies [5] [8] [11] showed that when using these techniques the percentage of usability problems detected by each inspector was rather low.