Who Finds what in Usability Evaluation

Abstract

For different levels of user performance, different types of information are processed and users will make different types of errors. Based on the error's immediate cause and the information being processed, usability problems can be classified into three categories. They are usability problems associated with skill-based, rule-based, knowledge-based levels of performance. In this paper, a user interface for a Web-based software program was evaluated by two groups - human factor experts and users. The experiment discovered that human factor experts are more effective than users in identifying usability problems associated with skill-based and rule-based levels of performance. Users are more effective than human factor experts in finding usability problems associated with the knowledge-based level of performance. The practical application of this research is also discussed in the paper.