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Tuesday, October 18, 2005

Web Usability: A Simple Framework

Web Usability is a big topic. I just Googled "Web Usability" and got 2,350,000 hits. "Web Usability Guidelines" is slightly more manageable, with only 598 hits. There is even a widely referenced research paper devoted to A Framework for Organizing Web Usability Guidelines.

[This reminds me of a saying I learned as a college student: "Those who can, do. Those who can't, teach. And those who can't teach, teach the teachers." Maybe if I scour Google for long enough, I'll find a framework for organizing Web usability frameworks. But I digress.]

I own several books on Web Usability, and I've looked at a far greater number of books and Web sites at one time or another. It's not hard to find long reading lists like this one by Paul D. Hibbitts. This appears to be a good list -- but who has time for that much reading? I will try to assemble a much shorter list of recommendations for a future post.

Despite (or maybe because of) the widespread attention to this topic, there are many ways to slice the usability pie, and each author seems to offer a different taxonomy. But all the best books do have one thing in common: their weight! No matter who you read, they give you a lot of guidelines to follow. In fact, far too many for my liking.

Being a simple-minded mathematician at heart, I am always looking for those few principles that will provide a sufficient foundation for most of what I need to remember. So, since I'm mostly interested in the role that site performance plays in determining usability, here is my own simple framework. I believe that to satisfy customers, a Web site must fulfill four distinct needs:

  • Availability: A site that’s unreachable, for any reason, is useless.

  • Responsiveness: Having reached the site, pages that download slowly are likely to drive customers to try an alternate site.

  • Clarity: If the site is sufficiently responsive to keep the customer's attention, other design qualities come into play. It must be simple and natural to use – easy to learn, predictable, and consistent.

  • Utility: Last comes utility -- does the site actually deliver the information or service the customer was looking for in the first place?

Until a customer has established a reason to stay on a site, I believe this framework presents the four essential qualities in order of their significance, and therefore applies to all first-time visitors. Familiarity with the site can alter a customer’s priorities, but only a prior knowledge of some unique utility not obtainable from other sites can overcome frustrating slowness or poorly designed navigation features.

For my purposes, this is enough detail. For the time being, at least, adopting this simple framework saves me from having to attend Jakob Nielsen's tutorial to learn Which of the more than 1,200 documented Web usability guidelines are most important? But I would hazard a guess that about 85% of those guidelines, and those proposed by other Usability experts, fall under my heading of Clarity.

On the other hand, I don't believe that issues of Clarity represent anything like 85% of the challenges to be overcome to make a site truly usable. Such an assumption would not give enough weight to the challenges presented by the other three areas. It would also downplay the dynamic nature of the Web experience and the interplay between these four factors as sites, and users' expectations of sites, evolve.

In particular, I believe that anyone responsible for setting site performance goals needs to understand how customers' expectations are likely to be modified by their experience of a site, and of the Web in general. And understanding what customers expect is the essential first step in providing a satisfying Web experience.

Eventually I plan to tackle this subject at the next level of detail. But first I may need to read a few more of the books on Paul Hibbitts' list!


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