User Information Needs
Information needs can vary widely, and each type of information need causes users to exhibit specific information seeking behaviors.
Users don’t always know exactly what they want.
During the process of finding, they may learn new information that changes what they’re looking for altogether.

User Information Seeking Behavior
Searching, browsing, and asking are all methods for finding, and are the basic building blocks of information-seeking behavior.
There are two other major aspects to seeking behaviors: integration and iteration.
Integrated browsing, searching, and asking over many iterations:

Berry-picking Model
These different components of information-seeking behaviors come together in complex models, such as the “berry-picking” model* developed by Dr. Marcia Bates of the University of Southern California. In this model, users start with an information need, formulate an information request (a query), and then move iteratively through an information system along potentially complex paths, picking bits of information (“berries”) along the way. In the process, they modify their information requests as they learn more about what they need and what information is available from the system.
Pearl growing Model
Users start with one or a few good documents that are exactly what they need. They want to get “more like this one.
” To meet this need, Google and many other search engines allow users to do just that: Google provides a command called “Similar pages” next to each search result. A similar approach is to allow users to link from a “good” document to documents indexed with the same keywords Del.icio.us and Flickr are recent examples of sites that allow users to navigate to items that share something in common; in this case, the same user-supplied tag. All of these architectural approaches help us find “more like this one.”
Learning About Information Needs and Information-Seeking Behaviors
Search analytics involves reviewing the most common search queries on your site as a way to diagnose problems with search performance, metadata, navigation, and content. Search analytics provides a sense of what users commonly seek, and can help inform your understanding of their information needs and seeking behaviors.
Contextual inquiry, a user research method with roots in ethnography, allows you to observe how users interact with information in their “natural” settings and, in that context, ask them why they’re doing what they’re doing.
Other user research methods you might look to are task analysis, surveys, and, with great care, focus groups.
Organization Schemes
Exact Organization Schemes
Exact organization schemes divide information up into well-defined, mutually exclusive sections, such as:
Alphabetical: for example, residential telephone book (white pages) sorted by surname then first names.
Chronological: for example, press releases sorted by date of announcement.
Geographical: for example, weather forecasts sorted by country and region.
Ambiguous Organization Schemes
Sometimes categories are overlapping or items fall into multiple categories.
Common ambiguous organization schemes include:
Topical: for example, product categories, newspaper articles, Open Directory.
Task-based: for example, browse, sell, search, sign in (limited number of high priority tasks).
Audience-based: for example, novice or expert.
Metaphor-based: for example, desktop or sketch map.
Multiple Organization Schemes
In the real world multiple schemes may be present together, However, when you start blending elements of multiple schemes, confusion often follows, and solutions are rarely scalable.
In the example below this hybrid scheme includes multiple schemes. Because they are all mixed together, users can’t form a mental model. Instead, we need to skim through each menu item to find the option they are looking for.

Where multiple schemes are presented on the same page:
Preserve the integrity of each organization scheme.
Do not mix and match schemes at the same level.
Taxonomies and Hierarchies
As far as possible, category labels should be:
- Phrased in the user’s language.
- Unambiguous.
- Mutually exclusive (non-overlapping), so users know where to look (scent). *
- Comprehensively exhaustive: i.e. completely partition the parent category, so users do not suspect a category is missing.
* If the categories are not mutually exclusive (i.e. if items may appear in multiple places), the taxonomy is called polyhierarchical.
Sometimes it makes sense to cross-list items in multiple locations: E.g. Do tomatoes belong to fruit, vegetable, or berries? Probably all of them [The tomato is technically a berry and thus a fruit, although it is usually used as a vegetable.]
Are toner cartridges best listed under laser printers or printer supplies? Probably both.
Hierarchies: Breadth Vs. Depth
If a hierarchy is too narrow and deep, users have to click through too many levels. If a hierarchy is too broad, users must choose between a large number of subcategories at each level.
A medium balance of breadth and depth provides the best results.
If you expect the hierarchy to grow, tend towards broad-and-shallow (it is less problematic to add items to secondary levels of the hierarchy).
Note: The famous 7 plus or minus 2 study [Miller, 1956] investigated the number of items retained in short-term memory. It does not apply to choices which are visible!
Card Sorting
Verify the hierarchical structure by conducting card sorting tests.
Open Card Sorting
Users cluster concept cards into their own categories and sub-categories, which they then label themselves.
Too few concept cards and you will not get two levels of a hierarchy, only one.
Used in early phases of research.
Closed Card Sorting
Users sort concept cards into a predefined category hierarchy.
At the start, you can ask users what they think each category means.
Used in later phases of research.
Faceted Search
A full text search generates an initial set of matching items.
These are then narrowed down using facets.
The user specifies a query progressively, narrowing down along one facet at a time.
The system can display the remaining number of items matching current facet values.
Dead-ends can be eliminated by not offering choices which would lead to 0 items.
Controlled Vocabularies
Using CVs with Search
A CV can be integrated with a web site’s search engine to handle the following situations:
- Synonyms: two words with the same meaning, like “jeans” and “dungarees”.
- Homonyms: words that sound the same, but have different meanings, like “bank” the financial institution and “bank” the side of a stream or river.
- Broaden or narrow a search.
- Common misspellings.
- Changes in content: for example, countries that change their name or have multiple spellings.
- “Best Bets”: identifying the most popular pages associated with a certain term.
- Connecting a woman’s married name to her maiden name.
- Connecting abbreviations to the full word: for example, NY and New York, the chemical symbol Si with the element Silicon.
User-Generated Structures
Allowing users to generate their own structures.
Watching user behavior and then supporting also known as “paving the cowpaths”.

Social Tagging
Web 2.0 and the rise of user-generated content has sparked a new form of emergent structure: collaborative tagging.
Also called free tagging, collaborative categorization. Users tag objects with one or more keywords. The network effect of “harnessing collective intelligence”.
Navigation Systems
Provide Spectrum of Navigational Aids
- Multiple Taxonomies: categories to browse.
- Search: Attribute and full text search.
- Site map: either graphical or a topical table of contents.
- Site index: alphabetical index of common words and phrases.



