Users and the Task of Information Retrieval

Essays in this search series:

• Considering Search: Search Topics
• Assumptions About Search
• Assumptions About User Search Behavior
• Types of Information Collections
• A Structural Look at Search
• Users and the Task of Information Retrieval
• Testing Search
• Useful Search Links and References

Search is information retrieval, but neither term really helps when it comes to understanding what users of a commerce site are doing. Users want to find something. I think online shoppers are more interested in locating that special something than they are in using a search mechanism per se; search is simply a tool, and as a tool should be appropriate to the needs of the user and to the general task of finding stuff.

Users bring different expectations and goals with them when they approach a search. One of the keys to designing -- and evaluating the success of -- a site's search function is understanding what's going on in the user's head when they interact with search.

So, search is a tool for information retrieval, but the transaction of searching encompasses more than just looking something up. When designing and testing your site's search mechanism, you must consider the following issues:

• As a general tool for information retrieval, considering the domain, does the search mechanism function appropriately?
• Given a range of common information retrieval tasks appropriate to your site, does the search mechanism function appropriately?
• Is search the best way to accomplish common tasks?
• Does the search mechanism accommodate a range of user expectations regarding information retrieval on your site?
• Does the search mechanism accommodate users who don't know how to formulate a query, or who don't enough to uniquely identify what they are looking for?
• Does the search mechanism appropriately handle queries against a product catalogue?

Searching as a Mode of Navigation

Not all users approach search as a means of information retrieval; various studies show that some users employ search as a way to navigate within a web site. According to Jakob Nielsen,

Our usability studies show that more than half of all users are search-dominant, about a fifth of the users are link-dominant, and the rest exhibit mixed behavior. The search-dominant users will usually go straight for the search button when they enter a website: they are not interested in looking around the site; they are task-focused and want to find specific information as fast as possible.

With most commerce sites centered around a product catalogue, this tendency to navigate via search makes it more difficult to design a search system that meets the needs of all shoppers.

Searching and Information Retrieval Expectations

Lou Rosenfeld and Peter Morville devote several sections in their book Information Architecture for the World Wide Web to discussing the varying needs users bring to search. They mention four kinds of expectation (the following descriptions are liberally paraphrased from the book):

Known-item searching

The user's information needs are clearly defined and have a single, correct answer.

Existence searching

The user knows what s/he wants but doesn't know how to phrase the query, or whether the answer exists at all.

Exploratory searching

The user knows how to phrase the query, but doesn't have a specific answer in mind; the user is essentially poking around.

Comprehensive searching (research)

The user wants everything available on a given topic.

Special Concerns With Searching a Product Catalogue

Users tend to search for products with a different in mind than when they search against document collections. When the user is in the mindset of "shopping", they usually are trying to accomplish any of a range of tasks; for example, with a scenario like shopping for a pair of khaki pants at an online clothing site, a user may have any (or several) of the following specific tasks:

• I want to find the khakis section
• I want to locate a specific pair of khaki pants; i.e., I know exactly what size, style, brand, material, and even pocket configuration of the pants I want
• I want to locate suitable khaki pants; no particular preferences, I want to see the selection of khakis that will meet my needs
• I want to locate a range of khaki pants in different styles and configurations, because I want to see if khakis are a fashion option for me
• I want to look at several kinds of pants, including khakis, because I need some new pants
• I want to be cool like those swing dancers on the Gap commercial
• I grew up wearing khakis, and they've always been "comfort" clothes for me
• I'm studying the rise of khaki pants as a cultural phenomenon, originating after world war 2 and continuing through this current phase of popular Gap commercials

These tasks generally aren't information related -- with the exception of that last one -- but rather are object related; that is, the user looks for a thing. Any meaning ascribed to the object is connotational. In contrast, information in a document collection is more denotational.

Any commerce site must study their customers and their market and develop a list of common user tasks. Users must be able to find products, and they must be able to follow paths appropriate to their own preferences.