Measuring Visual User Interface Complexity of Mobile Applications with Metrics

A crucial part of the design of mobile user interfaces is their evaluation with users. Although user studies are widely used for measuring the usability of a software system, they are time-consuming and expensive. In this study, we propose a novel approach which is based on the computational analysis of an app's visual appearance. By calculating metrics which measure the complexity of the user interface, it should be possible to draw conclusions about the perceived usability. Automating this practice would be beneficial to developers and designers, as it would help to find usability issues early and reliably in the software development life cycle. However, there is no tool available yet which allows to automatically quantify the complexity of a mobile application's user interface with metrics. We analyze the complexity based on screenshots of the user interface as well as on interaction data, without the need to access the source code of the application. We introduce a set of complexity metrics, which are partially based on existing metrics for the visual appearance of a user interface. In order to evaluate the quality of our metrics, we conducted a user study with several mobile apps. The results show that there are significant correlations between some of the proposed metrics and the perceived usability and workload.