ABSTRACT
In Chapter 2, the problem of developing a universal definition of usability was discussed. A universal definition will never capture all of the important factors of usability for every product because consideration of the context-of-use is essential in defining usability criteria, and this will be different for each system under investigation (Harvey et al., 2011a). One of the main purposes of defining criteria for usability is so that it can be evaluated. Usability evaluation is used to assess the extent to which a system’s HMI complies with the various usability criteria that are applicable in its specific context-of-use. The results of a usability evaluation can be used to indicate the likely success of a product with its intended market, to compare two or more similar products, to provide feedback to inform design, and even to estimate possible training requirements associated with the product (Butler, 1996; Rennie, 1981).
