For this section of the course, I read the following three books and one website.
Nielsen, Jakob. Designing web usability. Indianapolis, IN.: New Riders, 2000.
This book is the definitive book on web usability. It consists mainly of design heuristics and guidelines based on its author's years of experience with both the Web and pre-Web hypertext systems. Its major chapters cover page design, content, and site design. Later in the book, intranets, accessibility, international use, and future predictions are discussed. As the subtitle suggests, Nielsen stresses simplicity, clarity, and consistency in design.
Spool, Jared M. et al. Web Site Usability : A Designer's Guide San Francisco : Morgan Kaufmann Publishers, 1999.
Spool's book is particularly interesting because his findings are very empirical. After conducting 50 tests on 9 web sites, he reveals some of the trends discovered during those tests. One point is that web surfing is not the same as information retrieval. On the Web, user satisfaction is much less correlated with user success, as it is with traditional software. People may still enjoy a website very much, even though they have a difficult time completing set information-seeking tasks on that site. Other interesting findings, which contradict common usability notions, is that white space can have a negative impact on usability and that people do in fact scroll down.
Rosenfeld, Louis, and Peter Morville. Information architecture for the World Wide Web . Sebastopol, CA: O'Reilly, 1998.
This book is the definitive book on Web Information Architecture. It focuses primarily on how to structure information and then convey that structure to users. It covers organization structures and schemes, types of navigation, labeling systems, and search systems, all in some detail. It is very structured book, easy to read, and very helpful.
"Web Content Accessibility Guidelines 1.0." <http://www.w3.org/TR/WCAG10/> Last updated: 5 May 1999.
Published by the World Wide Web Consortium (W3C.org), these guidelines are to help designers determine how accessible their web sites are. There is much overlap with usability guidelines here, since what is easier for those with disabilities to use is often easier for everyone to use. Web sites can be graded on the extent they comply with WAI, ranging from "A" for sufficient compliance up to "Triple-A" for meeting all requirements.
Usability is an important aspect of web design. However, even among the experts, there is some conflict on what is usable and what isn't. Also, usability generally relies on the specific web site, the specific task, and the specific user. I think the best test of usability will always be actual tests of the site with real users. However, since this is costly and time-consuming, usability heuristics will always play an very important secondary role.
Below is a list of things to check when evaluating a website's usability. Though the criteria list does use a rating scale, the scores are neither objective nor equally weighted. They should not be summed for a total score. Be aware that some aspects actually conflict with each other. For example, standard link colors and underlining may actually hinder readability. Keep in mind that usability is only one aspect of web design. As Spool discovered, aesthetics and user enjoyment play very important roles as well. However, the more information-oriented your site, the more important usability will be. Most importantly, usability involves context, compromises, and conscious decisions. This list is a synthesis of the above readings and serves as a working checklist of usability issues, but it should not replace experience or common sense.
For each of the following criteria, a website should be ranked on a scale of 1 to 5, 5 being the best or highest score. A few example responses are given for each scale in order to provide basic guidance. When evaluating webpages of particularly horrible or even health-endangering usability, 0s are an option. Theoretically, 6s might also be possible, though very unlikely.
Is there a site identity such that a user will notice when they leave the site? Also, is there a global navigation system that conveys a "You Are Here" message?
How does the site use frames? Normally frames detract from usability, though in very rare cases they may be aides.
How much space is used for content? Most of destination page space should be dedicated to content. How much space is given to navigation, site graphics, or advertising? Is there anything that takes up more space than its usefulness warrants? Also, if a page is more than one screen in length, is it obvious that the content extends below "the fold"?
Is the page easily scanable for information pertinent to the user? Is navigation intelligently placed? Are headlines clear? Is there too much or too little white space?
Is the page easily read? It should include:
Are links standard colors? If not, are they at least consistent, with both visited and non-visited colors? Has the underlining been left intact?
Are the links related to the content, descriptive and predictable, including title attributes if necessary? Are there warnings if a link is a download or a format other than HTML? Are links predominantly text and not graphics?
Are links, especially navigation links, easily found and not embedded in text blocks?
Do links open new windows? If so, do they at least warn the user before hand? Are there any pop-up windows? Are any other browser navigational aids disabled or overridden: back button, status bar, bookmarks, history, etc.
Is it possible to determine how this site is structured? Likely options include: hierarchy, linear, web/hyperlinks, or database/tabular. Do the URLs mirror the structure? Is the main page helpful and orienting? Does it give a good impression of what the site contains and how to find it?
Does the use exact (alphabetical, chronological, etc.) or ambiguous (topical, task-oriented, etc.) organization schemes depending on the content? Is there a way to switch between schemes?
Is the navigation consistent? Is it in an easy-to-find location?
Is there an identifiable clustering or hierarchy in the navigation? Does the navigation mirror and convey the site structure? Is there a site map?
Is the navigation simple? Are branches at any level restricted to 7 plus-or-minus 2? Are destination pages fewer than 5 clicks from the main page? Is navigation clear text, or does it require user action to be discovered, as with a pull-down menu?
Is there a site search option? Is it possible to restrict the search to a certain area of the site? Can a user customize how the results are displayed? Does the system provide help in constructing better searches? Are the available options--search capabilities, ranking algorithms, etc--clearly visible?
Are the labels--links, titles, headings, etc.--clear? Are they specific and related to the content? Are they user-focused, and not too esoteric or domain-specific? Are they international in nature, meaning they are unlikely to confuse or give offense other cultures? If icons are used, do they also contain text? Are labels consistent across the site, using "standard" labels such as "shopping cart", "home," or "main" whenever possible?
Are graphics small and repeated wherever possible?
Are graphics used where color and text would have sufficed? This is most common on navigation bars.
Is multimedia (video, animation, sound) forced on the user or are there accessible controls? Are there any distracting animations that cannot be turned off? Are there alternatives for technologies that are more recent than 1 to 2 years?
Does the page use valid, standard HTML?
Will pages display at different screen resolutions and screen sizes?
How does the site look at different color depth settings?
Are the pages printable?
Does site degrade gracefully in old or non-standard browsers, such as those with no style sheet or scripting support?
Is there something worthwhile here? Why would users come here in the first place?
Are there any spelling or grammatical errors?
Can you tell who the author or publisher of the site is?
Does the site look good?
Does it feel polished and professional? Does it seem likely that a well established organization created this site?
Do you like the site?
What is your general impression of this site's usability? (You may also want to consider an average of all previous scores; however, after working through this list, you general impressions are probably more reliable.)
With these issues in mind, let's move on to other aspects of web interfaces!
| ~ztomasze Index:
LIS: Usability http://www2.hawaii.edu/~ztomasze |
Last Edited: 10 Oct 2001 ©2001 by Z. Tomaszewski. |