Usability Testing of World Wide Web Sites
Bureau of Labor Statistics: The life cycle of Web creation is identical to that of traditional software: requirements gathering, analysis, design, implementation, testing, and deployment. And, just as traditional software development should have a functionality and a usability component, so should Web development efforts. Usability can be defined as the degree to which a given piece of software assists the person sitting at the keyboard to accomplish a task, as opposed to becoming an additional impediment to such accomplishment. (2000-12-10)
The link address is: http://stats.bls.gov/ore/htm_papers/st960150.htm