Deceivingly Strong Information Scent Costs Sales

by Jakob Nielsen on August 2, 2004

Summary: Users will often overlook the actual location of information or products if another website area seems like the perfect place to look. Cross-references and clear labels alleviate this problem.


Information scent refers to the extent to which users can predict what they will find if they pursue a certain path through a website. The term is part of information foraging theory, which explains how users interact with systems using the analogy of animals hunting for food.

Predators following a strong spoor are firmly convinced that they'll find their prey at the end of the trail, and thus are less likely to be distracted and wander off the path.

Similarly, if users are clicking through a site hunting for specific products or answers, they'll keep going as long as they continue to find links that seem to take them closer and closer to their goal.

Information scent can backfire if a strong attractor seems to be the answer, but isn't. We found an example of this is in the teen area of kidshealth.org, which we recently tested in our study of how teenagers use the Web.

During our test, several teenage users failed the simple task of finding out how much they can weigh without being considered overweight. One of the site's articles, "What's the Right Weight for My Height?" is a great example of microcontent: it's explicit, short, and easy to understand. In addition to having a good title, the article is prominently featured in a site area entitled "Food & Fitness" — a label with attractive information scent for our users' assigned task. The article also comes up fairly high on a search for "weight."

Great so far. Except the article doesn't contain the answer to the question.

Unfortunately, because the path to the article has good information scent, and because the article itself has very strong information scent, our users concluded that the site didn't contain the required information. After all, they'd found the one place where this information ought to be, and it wasn't there.

Why Users Give Up

If the scent of information is sufficiently pungent, people are generally convinced that they're looking in the right place. If that place doesn't contain what they want, they're likely to conclude that the site doesn't offer it at all.

We've seen this effect in many other studies, and it often ends up costing websites sales. In our study of the usability of e-commerce sites, for example, users were looking for a baby seat for their car, and quite logically looked in the automotive section of one of the sites we were testing. No baby seats there, so no sale. Users assumed that the site didn't sell the product they needed because it wasn't in the category where they assumed they'd find it. (In fact, the product was in a different section of the site, without a cross-reference from the car area.)

Usually, of course, it's good when websites have both clearly defined navigation and labels that explicitly state what users will find at the other end of each link. The problem arises when some links are clear (and have strong information scent) and others are vague (and have weak information scent).

In the teen example, the site actually contains a very useful way to calculate whether people are overweight. The information, however, is located in an article called "Body Mass Index (BMI)." Yes, the title's short and explicit, but considered as microcontent, it has two problems:

  • The words are rather technical and intimidating. Users are unlikely to click on something like that unless they're good at math. Although located on a teen site, the title seems targeted more toward physicians.
  • Worse, the title doesn't communicate the article's content. The link leads to a discussion of the relationship between weight, height, and age and contains charts to determine whether somebody would be considered overweight.

Solutions: Cross-References and Clear Links

The standard solution to overly strong information scent is to provide a cross-reference to the desired location. Even if you don't consider baby seats car accessories, for example, you should feature a see-also link from the car area to the baby seats elsewhere on your site.

But cross-references only work if the see-also link has good information scent. In the teen website example, the article "What's the Right Weight for My Height?" actually contains a link labeled "body mass index" that would have led users to the answer they were looking for. But, because the link text had very low information scent relative to the users' goal, they overlooked it.

Check your website for pairs of links or navigation categories in which one label has strong information scent for something that's actually located elsewhere. If you find them, you're losing customers.


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