Context of Use
Web designers often say they spend a great deal of their limited time and resources working to improve their on-site search engines because, they believe, some people always rely on the search engine to reach their target content. They find further support for this assumption from Jakob Nielsen, who, in his book Designing Web Usability (New Riders), asserts that more than half of all users demonstrate "search-dominant" tendencies by going right to the search engine when they first visit a web site looking for content.
If this were true, designers would have their work cut out for them. Devising and producing a site that supports both visitors who prefer using the search engine and those who gravitate toward links presents a substantial challenge. Teams with limited resources find themselves having to support two separate paths to the same content. With perhaps thousands of pages of content, maintaining separate location tools becomes a monumental task.
In 2001, UIE's researchers put the user search-dominance theory to the test by conducting a study on e-commerce sites.
In the study, thirty users performed 121 different shopping tasks. Each user visited between three and six websites, shopping for items they were interested in purchasing. No two users were interested in exactly the same products.
If the search-dominance theory were true, a subset of these users should have always relied on the search engine to find product information, while others relied on the links. If at least a few users didn't consistently rely on the search engine, then the idea of search dominance would be in question.
Also, when looking individually at each site in the study, not all the users who visited a particular site should have employed a single strategy; samples of each kind of user behavior should have come up with each site.
To illustrate this point, consider the city or town where you live. Some of its inhabitants are right-handed, some left. In any restaurant in town on a Saturday night, you should expect to find some mix of lefties and righties. It is highly improbable that only right-handers would populate a random restaurant on a random Saturday night. UIE had a similar hypothesis for these web sites: it seemed highly unlikely that only search-dominant users would use a site during a given series of tests. Some of those users were bound to use links more than search.
The data from the study showed that there wasn't a single user out of thirty who always used the search engine first when looking for product information. While users often suggest that they have a preference for search, none of the users in the study actually were search-dominant. There were, however, some link-dominant users. About twenty percent of the study participants, in fact, chose links exclusively.
But even stranger, on fifty-three percent of the sites tested, each visitor stuck with a single location strategy—the same strategy employed by all the other visitors to that site. On twenty-one percent of the sites, every single user who visited the sites used search exclusively, and on thirty-two percent of the sites, users used only the links on the site. (The remaining forty-seven percent were a mixed bag, with users using both search and links.)
This implies there is something inherent to a site's design, rather than each user's hard-and-fast preference, that causes users to choose either the search engine or the links.
In other words, it appears that certain sites are search dominant, not users.
The data also indicated that one of the factors that predicted whether users would initially start with search or with links was the type of product being sold on the site. Certain types of products lend themselves better to being searched. For example, users typically rely on search to find a specific book or CD (more on this later), but tend to use links to find a particular item of clothing. The nature of the content on the site, it seems, can play a huge role in whether it is a search- or link-dominant site.
Users also often gravitated to the search engine when the links on the page failed to satisfy them in some way. Users seemed to use the search engine as a fallback after failing to pick up scent (a sense of the correct path to take to locate information) on the home page. UIE's study produced more evidence to support this behavior. UIE's researchers observed many home-page link failures that forced users to rely on the search engine.
Put another way: remember the winnowing step of item-selection that we identified in the catalog framework? Well, search is what gets used either when users can't sufficiently winnow on their own via catalog navigation or when the items being sought are easily searched for by name.
The lack of evidence to support the user search-dominance theory implies that teams may need to think about concentrating their efforts on a single content-location method. Depending on the specific content on the site, teams might want to focus specifically on either the search engine or the links, not necessarily both. UIE's testing suggests that focusing the resources on a single approach can dramatically improve the user's experience.
Regardless, it's clear that search is primarily used not because some people strictly prefer it or because it's faster, necessarily, but rather because a site lacks the trigger words a user may be seeking, or because of some other design-related reason. Trigger words are words that match the user's mental model of what she is seeking—for example, a Lunch Specials link when a user is seeking information on lunch specials.
Plainly and simply: the number one reason people use search systems is to resolve an error condition—the error of being unable to find content via site navigation.