Usability goals through the product design process[edit]
Usability goals must be included in every product design process that intends to follow a Human Factors approach (for instance, User-centered design[1] process or Usability Engineering Lifecycle[5]). They have to be clearly stated from the onset of the process, as soon as the end-users needs, risk of use, contexts and aims of use are identified (cf. “definition of usability goals” part).
Then, usability goals are used at each usability evaluation phase of the design process. Whatever the type of evaluation phase (i.e. formative or summative evaluation[6]), they are used to assess the performance of the users against the result of the evaluation process:
During formative/constructive evaluations (i.e. evaluations that occur during the design process to contribute to further improvement of the object under evaluation[6]), the comparison of the evaluation results against usability goals allows verifying whether those goals are met or not: as long as they are not met, the product under evaluation must be re-engineered to improve its usability. In this frame, usability goals allow also identifying usability flaws and therefore supporting this re-engineering process. They can also be used all along the iterations of the User-centered design process as indicators to follow-up the evolution of the system in terms of usability.
During summative evaluations (i.e. evaluations that try to give a definitive statement on the quality properties of a system under evaluation[6]), the meeting of usability goals means that the system is usable enough to go out the User-centered design[1] process and to be released.