Taxonomies and Classification for Organizing Content

1
Taxonomies and Classification for Organizing
Content

• Prentiss Riddle
• INF 385E
• 9/21/2006

2
What is a taxonomy?

• A hierarchical classification system in which
  categories are subdivided to create finer
  distinctions.

• animal
• vertebrates
• mammals
• cat
• dog
• reptiles
• invertebrates
• vegetable
• mineral

3
Not all classification systems are taxonomies

• Richard Saul Wurmans LATCH
• Location
• Alphabet
• Time
• Category
• Hierarchy

Any of these can be expressed as a taxonomy or
not. (Well, maybe not the alphabet...)
4
A quibble about definitions

• We commonly use taxonomy, hierarchy and
  classification system interchangeably but in
  fact theyre distinct (if overlapping) terms
• In particular, a hierarchy can be linear
• the H in Richard Saul Wurmans LATCH
• elephant gt horse gt dog gt mouse
• Maslows hierarchy of needs
• A folksonomy is not a taxonomy!

5
Why taxonomies?

• Taxonomies in our heads
• Fundamental to cognition
• Observed in children from an early age
• Long before Linnaeus and Darwin folk
  taxonomies

6
Why taxonomies?

• Taxonomies in the world
• Genealogy, phylogeny
• Command structures, org charts, territories
• Filesystems, domain names, URLs
• /var/www/people/faculty.php
• www.ischool.utexas.edu
• http//www.ischool.utexas.edu/people/faculty.php

7
This suggests the use of taxonomies in IA

• Taxonomies in support of browsing
• Taxonomies in support of search
• But thats problematic...

8
Problematic in the world

• The world is complicated
• Who here has had cataloguing?
• LC Subject Headings, LC Classification, Dewey...
• The world is even more complicated
• Lattices and networks, not trees
• Multiple kinds of relationships
• Fuzzy boundaries

9
Problematic in our heads

• The taxonomies in our heads dont match the world
• The available taxonomies may not be whats
  important anyway
• The user doesnt care about the org chart!
• (The mantra of enterprise IA)
• The user doesnt care about the filesystem

10
Cautious use of taxonomies

• Tempered by understanding and testing users
• Enlist users in creating taxonomies
• Techniques like card sorting
• Functional or folk etymologies preferred over
  official ones
• A gardening site might classify plants by
  temperature, sun and water needs, not by
  botanical classification
• Make official taxonomies available behind the
  scenes for use by experts (departmental admins,
  biology wonks)

11
Taxonomies in support of browsing

• Umbrella architecture
• (Rosenfeld Morville)
• E.g., familiar hierarchical menu structures

12
Taxonomies in support of browsing

• Not always ideal...

13
Taxonomies in support of browsing

• ...but better than chaos.
• Supports breadcrumbs
• If the users dont know your taxonomy, gives them
  a fighting chance to learn it.

14
Browsing very large taxonomies
Yahoo began as a taxonomy company ...although at
some point it became a search (and content)
company
15
Taxonomies in support of search

• Search results can include a link to a category

?
16
Taxonomies in support of search

• And searches can be limited to a category

?
17
Beyond taxonomies
18
Taxonomies on steroids

• Taxonomy controlled vocabulary
• thesaurus
• A thesaurus usually has a taxonomy embedded in it

19
Relationships in a thesaurus

• Some of the links in a thesaurus express
  hierarchy and links across it
• Broader term (BT)
• Narrower term (NT)
• Related term (RT)
• Some express the controlled vocabulary
• Preferred term (PT)
• Variant term (VT)
• Use (U)
• Used for (UF)

20
Not just synonyms

• A thesaurus is not just for synonym rings
• cat feline kitten kittycat
• Its also for key relationships across the
  hierarchy
• Nice pants! How about a shirt?
• In a sense, Amazons many suggestion features
  and much of Google Adwords are a set of RT links
  in a thesaurus

21
Faceted classification

• A problem inherent in taxonomies is, what gets
  divided first?
• History - U.S. - War - 1812
• War - History - U.S. - 1812
• U.S. - History - 1812 - War
• Or in more familiar terms
• Wine - Red - California - Dry - 1999- Under 25
• Wine - Under 25 - Red - Dry - California - 1999
• etc.

22
Facets are independent hierarchies

• Facets work in parallel
• In the subject classification example facets for
  topic, time, place, etc.
• In the wine example facets for type, origin,
  price, manufacturer, etc.
• A particular item will be at the intersection of
  several facets
• Facets can simplify classification systems both
  for creators and users

23
(No Transcript)
24
Folksonomies

• Fun, powerful, interesting but a misnomer not
  taxonomies at all
• Tagging systems in use in popular web 2.0 sites
• www.flickr.com
• del.icio.us
• Personal keyword metadata aggregated for
  searching and browsing
• The result is not a hierarchy, not really a
  classification system, certainly not a taxonomy