|
Tools, devices or software (as diverse as a TV remote control, the interface of an oven, or a word processor) must be evaluated before their release on the market from different points of view such as their technical properties or their usability. Usability evaluation allows assessing whether the product under evaluation is efficient enough (Are the users able to carry out their task while expending reasonable resources such as time, cognitive or physical demand), effective enough (Can the user complete the tasks they are supposed to perform with the tool? Is their performance complete and accurate?) and sufficiently satisfactory for the users (What is the users’ attitude towards the system? Do they experience discomfort?).〔International Organization for Standardization. Ergonomics of human system interaction - Part 210 -: Human centred design for interactive systems (Rep N°9241-210). 2010, International Organization for Standardization〕〔Nielsen, Usability Engineering, 1994〕 For this assessment to be objective, there is a need for measurable goals〔Salvemini A. V. Challenges for user-interface designers of telemedicine systems. Telemedicine journal, 5 (2), 1999〕 (for instance in terms of easiness of use or of learning) that the system must achieve. That kind of goal is called a usability goal (or also usability requirement〔〔Van der Peijl J et al. Design for risk control: the role of usability engineering in the management of use-related risks. J Biomed Inform(2012),http:/dx.doi.org/10 1016/j.jbi.2012.03.006〕). They are objective criteria against which the results of the usability evaluation are compared to assess the usability of the product under evaluation.〔 ==Usability goals through the product design process== Usability goals must be included in every product design process that intends to follow a Human Factors approach (for instance, User-centered design〔 process or Usability Engineering Lifecycle〔Mayhew. The usability engineering lifecycle: a practitioner's handbook for user interface design. London, Academic press; 1999〕). 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〔Brender J. Handbook of evaluation methods for health informatics. Burlington, MA: Elsevier; 2006.〕), 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〔), 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〔), the meeting of usability goals means that the system is usable enough to go out the User-centered design〔 process and to be released. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Usability goals」の詳細全文を読む スポンサード リンク
|