A Methodology for Structured Use-Centered Quantitative Full-Life-Cycle Usability Requirements Specification and Usability Evaluation of Web Sites

World Wide Web has gained its dominant status in the information and services delivery world in recent years, but how to build a good usability web site is still a problem. In this paper, we proposed a methodology for structured use-centered quantitative full-life-cycle usability requirements specification and usability evaluation of web sites. Our approach is that: the system’s usability is defined in terms of its consisting goal-tasks’ usability; a goal-task’s usability is defined in terms of several major usability aspects; each major usability aspect is further defined in terms of several basic use features. In this way, a quantitative web sites usability engineering framework is set up. According to this framework, each goal-task’s usability requirements are specified in terms of its basic use features, and then are tested against to see if they are satisfied; a system’s usability can be easily derived by combining its consisting goaltasks’ usabilities through a weighted scheme.