Strategy Patterns for Evaluating and Improving Usability

Patterns have had significant impact in many disciplines, particularly in software and web engineering, and we believe that they also provide a basis for selecting evaluation strategies via practical tips and tricks that can be easily adopted for evaluation and change projects. In this paper, we propose a holistic quality evaluation approach for usability and user experience (UX), which relies on quality views and strategy patterns. A quality view relates accordingly an entity super-category (e.g., product, system, system in use) with a quality focus (e.g., internal quality, external quality, quality in use). Usability and user experience are higher-level characteristics that should be linked to quality views appropriately. Also quality views support ‘influences’ and ‘depends on’ relationships between them. With a concrete evaluation or change project goal, our approach selects and instantiates a suitable strategy from a set of strategy patterns. Practical use of our approach is demonstrated through the specification and use of a strategy pattern in the evaluation of the Facebook mobile app.