Methodology for Evaluating the Usability of User Interfaces in Mobile Services

In this paper we present a usability measure adapted to mobile services, which is based on the well-known theoretical framework defined in the ISO 9241-11 [ISO 9241 (1988)] standard. This measure is then applied to a representative set of services of the Telefónica’s portfolio for residential customers. The user tests that we present were carried out by a total of 327 people. Additionally, in section 3 we describe the application of the methodology to a particular service and section 4 presents the results of the experiments. These results show highly significant differences in the three usability measures considered, though all of them have the same trend. The worst performers in all cases were the WAP and i-mode user interfaces (UI), while the best performers were the SMS and web based UIs closely followed by the voice UI. Finally, in section 5 we analyse the results and present our conclusions.