ABSTRACT
Usability engineering [Nielsen 1994b] is not a one-shot event where the user interface is fixed up before the release of a product. Rather, usability engineering is a set of activities that ideally take place throughout the lifecycle of the product, with significant activities happening at the early stages before the user interface has even been designed. The need to have multiple usability engineering stages supplement each other was recognized early in the field, though not always followed by development projects [Gould and Lewis 1985].
