The main usability criteria for the PDA to be accepted is that it should be pleasant to use and easy to learn. This phase of the design determines the important usability characteristics with their priorities, the usability attributes and the means of measuring them, the usability tracking table, the overall usability measure, description of the users and the confounding variables. As mentioned in the previous phases, we consider the unique aspect of our design to be the audio-based interaction mechanism. Therefore, this is again reflected in our experimental methodology in this phase of the project.
Efficiency implies the least time and effort.
If our interface fails in providing this attribute to the user, then our interface as a failure. That is the reason this attribute tops our priority list. Learnability Learnability for our interface can be defined as the ease with which the user gets to utilize the basic functionalities of the system. The dimensions are of course, time and effort. These functionalities include such basic tasks as looking up an address in the Address Book, scheduling an appointment, creating a memo document etc.