Accepted for Publication in the Software Quality Journal Usability and Quality in Use Measurement: A Roadmap for a Consolidated Model

Usability and Quality in Use Measurement: A Roadmap for a Consolidated Model Ahmed Seffah [email protected] Mohammad Donyaee [email protected] Rex B. Kline [email protected] Harkirat K. Padda [email protected] Abstract. Usability is increasingly recognized as an important quality factor for interactive software systems, including traditional desktop applications, Web-based systems, and mobile services. The design of this diversity of applications so that they actually achieve their intended purposes is not an easy task. Although there are many individual methods for evaluating usability, they are not well integrated into a single conceptual framework. This is true in part because there are now several different standards (e.g., ISO 9241, ISO/IEC 9126, IEEE Std.610.12) or conceptual models (e.g., Metrics for Usability Standards in Computing [MUSiC]) for usability, and not all of these standards or models describe the same operational definitions. This paper (1) reviews existing usability standards and models and (2) explains how these various approaches can be combined into a single consolidated, hierarchical model of usability measurement. This model is called Quality in Use Integrated Measurement (QUIM). Included in the QUIM model are 10 factors each of which corresponds to a specific facet of usability that is identified in an existing standard or model. These 10 factors are decomposed into a total of 26 sub-factors or measurable criteria, and these criteria are further decomposed into 127 specific metrics. The rest of this paper explains how a consolidated model, such as QUIM, can help in developing a more consistent approach to usability measurement.