Users and the Task of Information Retrieval

Essays in this search series:

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 [broken link 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.