Faceted Classification
Definition
A classification approach that describes items using multiple independent dimensions (facets) rather than a single hierarchy. Users can filter and combine facets to find what they need.
How It Works
Instead of one taxonomy tree, faceted classification uses multiple parallel taxonomies:
- Product: Laptops > Business Laptops > ThinkPad
- Brand: Lenovo, Dell, HP
- Price: Under 500-1000
- Screen Size: 13”, 14”, 15”
Users can combine: “ThinkPad + Under $1000 + 14 inch”
Advantages Over Hierarchical
- Flexibility: No single “correct” path to content
- Scalability: Add facets without restructuring
- Discovery: Users find things they didn’t know to look for
- No Orphans: Items naturally belong to multiple facets
Design Considerations
- Which facets matter to users? (not all attributes are facets)
- How many values per facet? (too many overwhelms)
- What’s the default view? (all facets shown or progressive disclosure)
- How handle items missing facet values?
Origin
Ranganathan’s Colon Classification (1930s): Personality, Matter, Energy, Space, Time (PMEST). The insight: complex subjects are better described by combining simple dimensions than by pre-coordinating into fixed classes.
Related: 02-molecule—taxonomy-design, 02-molecule—five-hat-racks