The Five Hat Racks
Overview
Richard Saul Wurman’s framework for information organization: there are only five ways to organize any information. Everything else is a variation or combination.
The metaphor: hats are units of information; hat racks are the structures we hang them on.
The Five Ways
1. Alphabet
Organizing by the sequence of letters. Works when users know the name of what they’re looking for.
Best for: Dictionaries, indexes, directories, reference lookups Limitation: Requires knowing the label; doesn’t reveal relationships
2. Time
Organizing chronologically or by sequence of events.
Best for: History, processes, schedules, version tracking, news Limitation: Emphasizes when over what or how; can lose the sense of one action affecting another
3. Location
Organizing by physical or conceptual space.
Best for: Maps, geographic data, spatial relationships, wayfinding Limitation: Only works when location is meaningful to the user’s task
4. Continuum (Magnitude)
Organizing by some measurable value (size, cost, importance, frequency, rating.
Best for: Rankings, comparisons, prioritization, dashboards Limitation: Requires a meaningful scale; can imply false precision
5. Category
Organizing by kind, type, or shared attribute.
Best for: Taxonomies, product catalogs, genre classifications Limitation: Categories are constructed, not discovered; different users may categorize differently
How to Choose
“The best way to organize information is the way that most easily reveals the aspects of a subject that you want to communicate.”
Ask: What question is the user trying to answer?
- “What is X called?” → Alphabet
- “When did X happen?” → Time
- “Where is X?” → Location
- “How does X compare to Y?” → Continuum
- “What kind of thing is X?” → Category
Combinations
Real information systems often combine hat racks:
- Category first, then alphabetical within each category
- Location as primary, time as secondary
- Continuum for sorting, category for filtering
The primary hat rack determines the dominant access path. Secondary hat racks enable alternative views.
The Deeper Insight
“The creative organization of information creates new information.”
The same facts, arranged differently, reveal different patterns. Choosing a hat rack isn’t just about access, it’s about what understanding becomes possible.
A hat-check clerk arranging by arrival time creates a chronological record. Arranging by hat type might reveal something about the event’s attendees. The hats don’t change; what we can learn from them does.
Application Questions
When designing any information structure:
- What’s the user’s primary question?
- Which hat rack best supports that question?
- What secondary access paths do users need?
- What patterns become visible (or invisible) with this organization?
Related:, 02-molecule—taxonomy-design