ᎏᎏ X CA/U ⫻ X CO/EXCA/E/XCA/U
2.8 Exercises
2.6.3 Conducting Usability Tests
Even a carefully designed system that uses the best theories must be evaluated in usability tests. Usability tests involve typical users using the system in realistic situations. All details of difficulties and frustrations the testers encounter should be recorded for the purpose of upgrading software quality. Most usability specialists use a variety of prototypes, from low- to high-fidelity methods. Low-fidelity methods, gener- ally used early in the design process, include index cards, paper stickers, paper-and-pen drawings, and storyboards. Storyboards are a graphical depiction of the outward appearance of the software system, without any actual system functioning. High-fidelity methods include fully interactive screens with the look and feel of the final software (Wickens et al., 2004).
When designers are conducting usability testing, whether early in the low-fidelity prototyping stages or late in the design lifecycle, they must identify what they are going to measure, often called usability metrics. Usability metrics tend to change in nature and scope as the project moves forward. In early con- ceptual design phases, usability can be evaluated with a few users and focuses on the qualitative assess- ment of general usability (whether the task can even be accomplished using the system) and user satisfaction. Low-fidelity prototypes are given to users, who then imagine performing a very limited sub- set of tasks with the materials or screens (Carroll, 1995). At this point, there is usually little to no quanti- tative data collection; simply talking with a small number of users can yield a large amount of valuable information. As the design takes on more specific form, usability testing becomes more formalized and often quantitative. Several versions of usability questionnaires are available, and some companies have developed their own usability testing metrics. In general, effectiveness, efficiency, and subjective satisfac- tion are the main usability measures.
Usability testing is not limited to product designs or software development. As computers become more popular, companies develop their websites, trying to attract more visitors by providing more serv- ices. In many cases, it is really difficult for a user to find what he or she wants from websites, especially when the website contains tremendous amounts of data. For example, Yu et al. (1998) reported that the Kodak website (www.Kodak.com) contained over 25,000 pages and 74,000 files in 1998. In terms of traf- fic size, Kodak.com averaged around one million hits daily, including roughly a quarter of a million pages viewed and accessed by some 24,000 unique visitors each day. However, the main top-level design remained unchanged, and the visitors had a hard time finding what they wanted as a result of broken links and unmatched menu structures. The effort to develop a new design was started from the guestbook of Kodak.com, which provided important information on what the visitors wanted most (user’s needs) and which problems the visitors had (user’s behavior). As seen in this Kodak.com case, users are the core factor of design. No products will be favored without considering the user. In response to the growing demands for usability, the U.S. Department of Health and Human Services developed a website about usability (http://www.usability.gov/). This website provides useful information such as federal guidelines, Internet statistics, and lists of usability-related events.
2. What software program do you frequently use? Do you like the software? Why? What feature of the program do you like the least? Why? How do you want to change it? Do you think it is acceptable to most users?
3. Do you or anyone you know have any work-related illness or injury? How do you know it is work related? If it is work related, has the employer made a modification of the workplace? If so, has the incidence rate decreased?
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