Comparing telephone-computer interface designs: Are software simulations as good as hardware prototypes?

Widespread interest in the evaluation of human-system interfaces has led to the development of various techniques in usability engineering. Usability evaluations are usually carried out on interface prototypes. However, if the design involves hardware implementation, such as a special keypad or a control panel layout, producing hardware prototypes for evaluation can be expensive and time-consuming. One solution to this problem is to use software tools for design simulation. In this case, a question which must be answered is: will a simulated prototype produce the same conclusions as a hardware prototype? That is, is software simulation a valid approach? The main purpose of this paper is to address this issue through an experiment. A multimedia authoring package was used to simulate several potential telephone handset designs for telephone-computer interfaces. The simulated prototypes were tested and compared with a physical keyboard for validation. The experiment did confirm the validity of simulation in this particular setting. It also demonstrated the advantages of using a software tool to build the prototype and to automate the evaluation process, including user training, test setting, and data collection.