The latter includes maintaining a development web site on which user interface changes can be prototyped, tested, and perfected before introducing changes to the production web site. Change control, however, is more than just having a development or staging site that is separate from the production site. It also involves maintaining a design document, or at the very least, a written set of user interface requirements. Finally, there should be formal processes for deploying new content into production. Some people rationalize that usability testing is very costly and complex, and therefore cannot be justified.
Repetitive testing is necessary as the human interface design is changed and refined.
The incremental cost and time for testing and other controls can be justified in terms of the quality cues that the web site gives to prospective customers. Customers typically use quality cues in choosing between brands. With an e-commerce web site, the first quality cues come from the human interface. Human Interface Design Designing the human interface to an e-commerce web site should focus on gaining the user's attention, orienting the user to the business that will be transacted, and retaining the user's attention. The goal is to achieve active participation by the user in the web site.