Though web usability is a relatively new field, there are already a number of common criteria used in judging a web site's usability. The following list of criteria is one of my own devising. The evaluated aspects were chosen based quite heavily on Jakob Nielsen's book, Designing Web Usability.[1] CNET's Builder.com was also consulted. [2]
The criteria were then applied to a website: the Web Developers Virtual Library at WDVL.com. It is a casual site aimed at web developers. It has a large collection of web-oriented resources, articles, tutorials, and software reviews. I enjoy the content and find the site relatively easy to use.
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.
The score and comments in the tan boxes are my evaluation of how WDVL.com measures up.
Is there a site identity such that a user will notice when they leave the site?
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WDVL: 5 One of most consistent sites I've ever seen. The right nav bar is always there, the same top graphics, the same colors, the same fonts. |
How does the site use frames? Normally frames detract from usability, though in very rare cases they may be aides.
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WDVL: 5 No frames used. |
How much space is used for content? Most of the page space should be dedicated to the content. How much space is given to navigation, site graphics, or advertising? Is there anything that takes up more space than its usefulness warrants?
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WDVL: 4 The main page isn't bad, but other pages are pretty poor, especially the huge yellow area at the top of every page. With long articles, this is less of a concern (ie, the percentage of space lost goes down). They could remove the side navigation bar within articles, but I think would negatively impact site image and consistency. |
Is the page easily scanable for information pertinent to the user?
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WDVL: 4 The organization of the main screen, topic navigation screens, and the nav bar is very good, thanks to a large font size and different text colors. The type can be a little large at times, but for amount of info per screen, good job. |
Is the main screen helpful and orienting? Does it give an impression of what the site contains and how to find it?
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WDVL: 4 The main page includes a smattering of the latest articles, nav bars -- both down the side and along the top -- and other interfaces (beginner or intermediate) to go to. Not a site map, but a good mix over all. |
Is the page easily read? It should include:
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WDVL: 4 Uses a standard sans-serif font, slightly off-white background (a good thing), some margins. Easy to read online. |
Are graphics small and repeated wherever possible?
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WDVL: 5 Good job here. Header graphic used consistently; one or two other small images used repeatedly. |
Are graphics used where color and text would have sufficed? This is most common on navigation bars.
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WDVL: 4 Good job. Could have had only a text header (but I like the graphic). |
Is multimedia (video, animation, sound) forced on the user or are there accessible controls? Are there any distracting animations that cannot be turned off?
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WDVL: 4 No site multimedia. Some irritating banner ads, but placed at a spot that could easily be scrolled off the screen. |
Are links standard colors? If not, are they at least consistent, with both visited and non-visited colors? Has the underlining been left intact?
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WDVL: 2 Consistent non-standard colors and no underlining. Good placement most of the time though, so it's not as bad as this 2 seems. (see "Link Placement" below) |
Are the links descriptive and predictable, including title attributes if necessary? Are there warnings if a link is a download or a format other than HTML?
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WDVL: 4 The link descriptions (ie, article summaries) on the topic pages are superb! My only complaint is I would have liked to see some link titles on the many acronyms on the standard right nav bar. |
Are links, especially navigation links, easily found and not embedded in text blocks?
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WDVL: 4 Links to further references are at the ends of articles . Nav bar and article titles in topic summaries imply links, though the links are not a standard color or underlined. Though there is no underlining, most links are either bright red, in a single column, or in a standard location. |
Do links open new windows? If so, do they at least warn the user before hand?
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WDVL: 5 Links do not open new windows. |
Is the navigation consistent? Is it in an easy-to-find location?
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WDVL: 5 That right nav bar is a big help here. Also, links are very consistent between article pages. |
Is there an identifiable clustering or hierarchy in the navigation?
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WDVL: 4 Good hierarchical clustering. |
Is there a site search option?
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WDVL: 3 An average search facility. Depending on which page you search from, you get a different site identity for the search results, which is disorientating. |
Will pages display at different screen resolutions and screen sizes?
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WDVL: 4 Some pages take up more than a screen width at anything below 1024x768. The saving grace is that usually it is only part of the right nav bar that can't be seen; the page is still readable for most purposes. |
How does the site look at different color depth settings?
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WDVL: 4 Uses unsafe colors, but degrades decently. Still looks basically the same at 256 colors. |
Are the pages printable?
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WDVL: - - I don't have a printer |
Does site degrade gracefully in old or non-standard browsers, such as those with no style sheet or scripting support?
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WDVL: 5 Looks clunky, but still very readable, even in Netscape 2.0. |
Is there something worthwhile here? Why would users come here in the first place?
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WDVL: 5 The content is fantastic. It is leading reason why I have this site as my browser home page. |
Are there any spelling or grammatical errors?
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WDVL: 5 Good editors! |
Can you tell who the author or publisher of the site is?
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WDVL: 5 Every article has a link to a brief bio of the author and usually a link to their own website. |
Does the site look good?
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WDVL: 3 I don't like the colors very much, especially the yellow with red text. |
Does it feel polished and professional? Does it seem likely that a well established organization created this site?
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WDVL: 3 The site seems pretty casual. |
Do you like the site?
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WDVL: 4 I like it. |
What is your general impression of this site's usability?
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WDVL: 4 It's consistent, has good content, decent navigation, and a number of different paths to information. |
What is the average of your usability ratings? This is a decent estimate of the site's overall usability. It is not very exact because each of the criteria above should probably not be equally weighted, as they are here.
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WDVL: 4.3 |
I think I have followed a relatively standard usability criteria here. Yet still I notice that some criteria can be mutually exclusive. Underlining all links in a block of text can negatively impact readability. Including navigation on all pages to improve site image and navigation is likely to degrade the screen real estate ranking.
I'd also like to point out that usability, though currently a hot topic, is far from the only consideration in designing webpages. It has been shown [3] that, much more than with software, there is often a discrepancy between the success a user has with a site and their enjoyment in using it. Though this seems contradictory at first, it is possible to build a website that is easier to use--that increases user task success rates--and yet find that users still don't like to use it. Indeed, I think user satisfaction is more important than usability: it is what determines how much your site is used.
Part of this discrepancy may arise from the fact that not all sites are strictly informational. Some are good for casual browsing, not specific searching. Often web users are not looking for a specific item or fact, but hoping to learn about some general topic or to browse a certain store. (For example, about half of my reading at WDVL.com begins from a current article link on the home page; I may never use the right navigation bar once during a whole session.) There is an artistic, entertaining, serendipitous side to webpages. Yet usability is based on rigidly engineering a site for rapid navigation and accurate information retrieval.
Of course, as in all things, a balance is the best choice. Usability should be implemented as much as possible. (Though focusing only on high usability may not necessarily increase user satisfaction, low usability will likely decrease user satisfaction.) But it must be remembered that this can lead to designs that lower user satisfaction or enjoyment. This can be a sign that the designer has taken usability principles too far.
1. Nielsen, Jakob. Designing web usability. Indianapolis, IN.: New Riders, 2000.
2. "CNET Builder.com -- Web Graphics -- Critique of the Week." <http://builder.cnet.com/webbuilding/pages/ Graphics/Critique/index.html> Accessed: 06 March 2000.
3. Spool, Jared M. et al. Web Site Usability : A Designer's Guide San Francisco : Morgan Kaufmann Publishers, 1999.
| ~ztomasze Index:
LIS: Web Interface Critique http://www2.hawaii.edu/~ztomasze |
Last Edited: 08 Mar 2001 ©2001 by Z. Tomaszewski. |