Cataloging and Classification/Other subject controlled vocabularies

Word-based classification
Several public libraries have explored the option of "word-based" classification in the 2000s and 2010s. Instead of grouping books using complex strings of numbers, as they would when using the Dewey Decimal system, they instead categorize books using regular language terms. Many libraries that use these "word-based" systems base their controlled vocabulary on the Book Industry Standards and Communications Subject Codes (BISAC). Though BISAC, like Dewey, offers complex alphanumeric strings for categorization, "Dewey-free" libraries generally use only the full English terms when categorizing books.

A quick comparison of the two systems provides some interesting contrasts. Dewey, as a rule, takes far more subcategories to express a concept than BISAC does (look at the long, complicated categorization necessary for denoting Soccer in Dewey). On the other hand, BISAC's relative simplicity means that several concepts can't be expressed exactly (UFOs, Taoist philosophy, Hadith, Lesbians, Zebras, Russian Revolution). Both show a bias towards the United States (the American Civil War is simpler to express in both systems than the Russian Revolution) and other colonial powers (neither system is capable of expressing the concept of Nigerian Poetry). A bias towards Christianity is also evident (both provide very simple expressions for Christian Bibles, but not for the Muslim Hadith).

Advocates of BISAC-based systems say that abandoning Dewey's unintuitive numeric strings in favor of BISAC's simpler categorizations makes non-fiction collections easier for patrons to browse by themselves. Skeptics point to the difficulty of expressing exact concepts in BISAC's general categories, and say that using such broad categories makes it more difficult to find a particular book. Both advocates and skeptics agree that BISAC is better suited to small public libraries with smaller collections, where each of BISAC's categories will include dozens, rather than hundreds, of books.