Certain key architectural components are manifest completely in the background; users rarely (if ever) interact with them. These components often “feed” other components, such as a thesaurus that’s used to enhance a search query. Some examples of invisible information architecture components include:

Controlled vocabularies and thesauri

Predetermined vocabularies of preferred terms that describe a specific domain (e.g., auto racing or orthopedic surgery); typically include variant terms (e.g., “brewskie” is a variant term for “beer”). Thesauri are controlled vocabularies that generally include links to broader and narrower terms, related terms, and descriptions of preferred terms (aka “scope notes”). Search systems can enhance queries by extracting a query’s synonyms from a controlled vocabulary.

Retrieval algorithms

Used to rank search results by relevance; retrieval algorithms reflect their programmers’ judgments on how to determine relevance.

Best bets

Preferred search results that are manually coupled with a search query; editors and subject matter experts determine which queries should retrieve best bets, and which documents merit best bet status.

Whichever method you use for categorizing architectural components, it’s useful to drill down beyond the abstract concept of information architecture and become familiar with its more tangible and, when possible, visual aspects. In the following chapters, we’ll take an even deeper look at the nuts and bolts of an information architecture.