Mobile Text Entry

There has been a substantial growth in interest in mobile text entry over recent years, among both researchers and users. Increasingly mobile devices are being used to perform text-intensive applications, such as text messaging, creating a demand for more efficient and easier to use text entry methods. Unlike for desktop computing, no single, standard mobile text entry method has emerged. The diversity of mobile devices makes it unlikely that this will ever occur. Thus, mobile text entry remains a very open area of research, providing a favourable environment for the development of innovative text entry methods. A necessary part of the development of a new mobile text entry method is a comparison of its performance with existing methods. Despite being coinplex and time consuming, empirical evaluations remain the best way to make these comparisons. A review of current best practice for the empirical evaluation of mobile text entry methods is presented, alongside a classification of existing mobile text entry methods. The results of an empirical evaluation of a new mobile phone text entry method called Fastap are reported. The performance of the new method, along with that of the T9 and multi-press with timeout mobile text entry methods, was measured for the entry of four different types of text and with three different levels of user experience. The Fastap method was found to provide the best immediate usability among the three methods and its performance continued to improve as users gained more experience with it. Fastap also performed strongly in the subjective ratings. The results of the evaluation are very positive for the ongoing development of the Fastap interface.