Jakob Nielsen's reputation as a Web usability expert makes his writings required reading for Web builders. You may not agree with all of his conclusions and recommendations, but you should be aware of them nonetheless. In the Sept. 13, 2004 edition of his Alertbox, he makes a case for standardizing numerous details of Web page design.
As usual, he bases his usability recommendations on solid research and observations. However, I believe his conclusions, and especially his recommendation to standardize design, are slightly off base. I suggest a somewhat different interpretation of his basic observations.
The case for standardization
One of his key points is that Web visitors view the Web as one large, integrated resource; therefore, they expect a degree of consistency in the common user interface elements that appear on most Web pages. He also reminds Web builders that visitors spend most of their time on other Web sites, and they arrive at your site with expectations based on experiences at those other sites.
He goes on to analyze the treatment of several design elements on more than 50 different Web sites, and rates the degree of consistency using the following criteria:
- Standard: Elements that receive the same treatment on more than 80 percent of the Web sites. According to him, visitors expect these elements to always work the same.
- Convention: Elements that receive the same treatment 50-79 percent of the time. Visitors expect these elements to usually work the same.
- Confusion: Elements that receive the same treatment 49 percent of the time or less. Visitors don't know what to expect when they encounter these elements on a new Web site.
According to the article, here's the breakdown of the standardization of the design elements on the surveyed Web sites:
- Conforming to standard: 37 percent (examples: a logo in the upper left corner, a search box on the home page)
- Conforming to convention: 40 percent (examples: distinctive color for visited links, shopping cart links in the upper right corner of the page)
- Confusing treatments: 23 percent (examples: location of the main navigation scheme, search box, and help)
His interpretation of this data is that inconsistent treatment of nearly a quarter of the design elements commonly found on Web pages causes usability problems for visitors, and that Web builders should address this deficiency by adopting design standards for those elements.
Suggesting standards with a spin
I believe he's right on target when he stresses that usability is a matter of meeting user expectations. However, I differ with his conclusion that greater standardization of Web page design is the best (or only) way to achieve better usability.
First, let's consider what visitors really expect. I think he goes a little too far with his assumption that visitors perceive the Web as a "single, integrated resource." The question is: How thoroughly integrated do visitors expect various parts of the Web to be? To draw a shopping analogy, he seems to think visitors expect the Web to be like one big department store, where the same rules apply throughout the store even though different departments may sell different products. I suggest that user expectations may be more like a mall or shopping center, where several stores share a common location and may keep the same hours, but each store has its own distinct identity. Shoppers tolerate, and even expect, some differences from store to store. After all, it's those differences that give each store its unique appeal. I think the same applies to Web sites.
If you accept the premise that visitors will tolerate a degree of inconsistency between Web sites in order for those sites to have individual identities, then the fact that some elements don't receive the same treatment on most Web sites doesn't necessarily make those elements confusing. In fact, it's quite possible that multiple treatments exist for a given design element (e.g., the location of the main navigation scheme), and visitors can recognize and use any one of those treatments without difficulty, even though none of the solutions meet his statistical test for a design standard or convention.
The real test of Web site usability is how well visitors can find what they're looking for on the site. A site design might conform to a set of design standards and conventions derived from common practices on other sites and still not create a good user experience because the site organization isn't obvious to the visitor, or because it just isn't visually appealing. Another site might break from the standards in many areas yet still be highly usable if it presents the visitor with clear and obvious organization and choices.
Be aware of the emerging and evolving standard practices for treatment of common design elements, and how those standards influence user expectations. However, I don't believe that effective Web site design is likely to be the result of following a codified set of design standards. On the contrary, great design intelligently and selectively diverges from the standards in a continuing effort to find even better solutions to design challenges. That's a process that is likely to continue to defy statistical analysis. But then, that's why design is an art rather than a science.