Model-based approaches to quantifying the usability of mobile phones

Several factors make it difficult to quantify the usability of mobile phones. Nevertheless, a quantified value of the usability could be used for several purposes, such as design innovation and benchmarking. This paper proposes three approaches (task centred, usability indicator-based, and design area-based quantification) to quantifying the usability of mobile phones on the basis of a hierarchical model of usability factors. Each of them provides process and rules for calculating the usability score of a mobile phone by applying weighting value assignment methods. Through two case studies, we could obtain empirical data to be used for determining the weighting value for quantification and confirm the usefulness of the proposed approaches.