Single-selecting and/or multi-selecting facet values

‘While you could choose to allow multi-select elements for some facets and single select elements for others, the drawbacks of the inconsistent behavior may outweigh any functional benefit.’

Decision tree: Single-select, multi-select, or mix? (PDF)

From Mike Padilla: User Interface Implementations of Faceted Browsing

Classification schemes (and when to use them)

Classification schemes:

  • Alphabetic
  • Geography
  • Format
  • Organisational structure
  • Task
  • Audience
  • Subject/Topic

If appropriate

  • Mix up types at each level
  • Start with one type and use a different type at the next level.
  • Use more than one approach for your whole content set.

Donna Spencer: Classification schemes (and when to use them)

Faceted Search

  1. Decide on your filter value-selection paradigm—either drill-down or parallel selection.
  2. Provide an obvious and consistent way to undo filter selection.
  3. Always make all filters easily available.
  4. At every step in the search workflow, display only filter values that correspond to the available items, or inventory.
  5. Provide filter values that encompass all items, or the complete inventory.

G. Nudelman: Best Practices for Designing Faceted Search Filters

Benefits and problems of faceted classification

Benefits of faceted classification:

  1. Do not require complete knowledge of an individual items
  2. Do not require knowledge about relationships of items
  3. Classes are hospitable, can accomodate new entities easily
  4. Classes are flexible
  5. Classes are expressive
  6. Classes can be ad-hoc and free-form
  7. Clases allow many different aspects on and approaches to the items

Major problems of faceted classification:

  1. Choosing the right facets
  2. Lack of ability to express relationships between facets
  3. Lack of ability to visually express the scheme

William Denton quoting Barbara Kwasnick (1999) The role of classification in knowledge representation and discovery. Library Trends 48 (1): 22-47

Faceted classification

“This is a faceted classification: a set of mutually exclusive and jointly exhaustive categories, each made by isolating one perspective on the items (a facet), that combine to completely describe all the objects in question, and which users can use, by searching and browsing, to find what they need.”

From: Denton, William (2003), ‘How to make a faceted classification and put it on the Web’, [online] Available: