Civil Engineering Reference
In-Depth Information
User-based evaluations involve testing by users. There are several methods:
• Usability testing
• User participatory design
• Thinking aloud
• Questionnaires and interviews
These methods are discussed below.
HEURISTICS EVALUATION
Heuristics evaluation refers to a set of rules or design goals that are used to evaluate an
interface. These are usually formulated at a high level with abstract goals, and it is up to
the designer to determine how each goal can be implemented in terms of interface design.
For example, one high level goal is “Speak the user's language.” The analyst will then
interpret what this implies in terms of interface design. To implement this heuristic we
must understand the following:
• What exactly is the users' language. How do users refer to various items?
• How do users think about their task?
Based on this knowledge the analyst will understand better what words to select for
dialog design and for menus.
Shneiderman (1998) proposed eight “golden rules” for interface design, but he
remarked that there is a need to validate and interpret these rules for different
applications. The golden rules are shown in Table 7.5. Nielsen and Molich (1990) and
Nielsen (1994) proposed ten usability heuristics. These have become widely used and are
the best known set of usability heuristics (see Table 7.5). Many other researchers have
also developed recommendations. Bruce “Tog” Tognazzini's list of first principles of
interaction design is interesting reading (Tognazzini, 2004).
COGNITIVE WALKTHROUGH
Cognitive walkthrough (CW) is a method for evaluating user interfaces by analyzing the
mental processes that are required of users (Lewis and Wharton, 1997). It is performed by
an analyst, and real users are therefore not used in this type of analysis. CW can be
performed at any stage of the design cycle. At the early stages of design,
TABLE 7.4
Shneiderman's Eight Golden Rules
1. Strive for consistency
2. Enable frequent users to use shortcuts
3. Offer informative feedback
4. Design dialogues to yield closure
5. Offer error prevention and simple error handling
6. Permit easy reversal of actions
7. Support internal locus of control (user in control of the system)
8. Reduce short-term memory load
