Supporting user-perceived usability benchmarking through a developed quantitative metric

Most user-centered assessment activities for ensuring usability are principally focused on performing formative evaluations, enrolling users to complete different tasks and thus obtaining indicators such as effectiveness and efficiency. However, when considering broader scenarios, such as in User Experience (UX) assessments, user perceived satisfaction (or perceived usability) is even much more relevant. There are different methods for measuring user perception, however most of them are mainly qualitative and based on individual assessments, providing little specific support to carry out comparisons-i.e., benchmarking on user-perceived usability. In this paper, we propose a quantitative metric to achieve comparative evaluations of usability perception based on Reaction Cards, a popular method for obtaining the user's subjective satisfaction in UX assessments. The metric was developed through an empirical study. Additionally, it has been validated with usability experts. Besides, we provide a supporting tool based on the developed metric, featuring a framework to store historical evaluations in order to obtain charts and benchmark levels for comparing perceived usability from different artifacts such as software products, applications categories, services, mockups, prototypes and so on. Furthermore, an evaluation involving usability professionals was achieved, providing satisfactory results to answer research questions, thus demonstrating the suitability of the approach proposed.