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10.4 Types of usability testing or usability inspections 269

to the interface in question. Heuristics are short sets of usually no more than 10 inter-
face rules. To be truly effective, the expert must be very familiar with the heuristics
and have previous experience in interpreting them. Lazar provides a list of various
sets of heuristics for different types of websites (Lazar, 2006) but the best-known set
of broad interface heuristics is probably Shneiderman’s 8 Golden Rules of Interface
Design (see Table 10.2).

Table 10.2 Shneiderman’s 8 Golden Rules of Interface Design

Strive for consistency
Cater to universal usability
Offer informative feedback
Design dialogs to yield closure
Prevent errors
Permit easy reversal of actions
Support internal locus of control
Reduce short-term memory load
(Shneiderman et al., 2017)

In a consistency inspection, one or more experts review a series of screens or web
pages for issues of consistency in layout, color, terminology, or language. Sometimes,
an organization has a specific set of style guidelines (for colors and typefaces) and a
consistency inspection can check for overall consistency with those style guidelines.
A cognitive walkthrough is an expert review method in which interface experts
simulate users, “walking through” a series of tasks. The experts must have experi-
ence with general interface design and a good understanding of who the users are
and what tasks they are expected to perform in the interface that is being evaluated.
Because of the exploratory nature of a cognitive walkthrough, it can give an under-
standing of how users might interact with an interface the first time that they attempt
to use it (Hollingsed and Novick, 2007). Both high-frequency tasks and rarely occur-
ring but important tasks (such as error recovery) should be included in a cognitive
walkthrough (Shneiderman et al., 2017). Because it is task-based, rather than rule-
based for experts, it is still somewhat controversial, as some people feel that it is not
as productive as user-based testing.
Not as popular as the previous three methods, but still occurring often, is the
guidelines review, in which an expert compares a set of interfaces to a previously
written set of interface guidelines. While this sounds like a heuristic review, the main
difference is that a guidelines review uses a large set of guidelines (usually 10–200).
Heuristic reviews take place more often because they are easier and take less time.
However, guideline reviews are more thorough. Probably one of the best-known sets
of guidelines is the Web Content Accessibility Guidelines (WCAG, currently in ver-
sion 2.0), created by the World Wide Web Consortium (http://www.w3.org/WAI).
These guideline documents provide guidance on making website content accessible
for people with disabilities. Internationally, most laws that deal with accessible web