ABSTRACT
The first references to the concept that is now most commonly known as ‘usability’ used terms, such as ‘ease of use’ (Miller, 1971, cited in Shackel, 1986), ‘user friendliness’ (Dehnig et al., 1981), and ‘user-perceived quality’ (Dzida et al., 1978). It was widely thought that these terms created a narrow view of the concept in which the person is treated as a single system component (Adler and Winograd, 1992; Bevan, 1991). This traditional view was criticised for overlooking users’ cognitive and social characteristics and not considering the processes of learning and adaptation to systems and products (Adler and Winograd, 1992). It also suggested that usability is a characteristic that can simply be designed into a product (Bevan, 1995) and failed to account for other influencing factors, such as users’ past experiences and their expectations and attitude, as well as the features of the product itself (Baber, 2002). In response to this criticism and to calls for a more precise definition (Norman, 1983), the term usability was adopted, with the first attempt at a definition being widely attributed to Brian Shackel in 1981 (Baber, 2002; Shackel, 1986). Early definitions of usability were based on the usability of computer software (Dehnig et al., 1981; Long, 1986; Ravden and Johnson, 1989; Sweeney et al., 1993). This is because the term was most commonly associated with the field of HCI. In the 1970s and 1980s, people only encountered computers at work, and so definitions of usability dealt primarily with work contexts. More recently, however, the gulf between computers and ‘ordinary people’ has reduced dramatically (Cox and Walker, 1993), and definitions of usability have widened to encompass any product or system with which a user interacts, whether for work or for leisure purposes. Bevan (1999) documented this transition in the view of usability from computer-related to a broader view, and added a final stage to the development of usability: the realisation that usability should be a central goal of design. This reflects the increase in the importance of this concept
since it was first defined, which has been driven by a decline in users’ acceptance of poor design and the increasing complexity of products (Stanton and Young, 2003).
