UC Berkeley

The paper aims to explain the character and causes of obsolescence in assigned subject descriptors. The paper takes the form of a conceptual analysis with examples and reference to existing literature. Subject description comes in two forms: assigning the name or code of a subject to a document and assigning a document to a named subject category. Each method associates a document with the name of a subject. This naming activity is the site of tensions between the procedural need of information systems for stable records and the inherent multiplicity and instability of linguistic expressions. As languages change, previously assigned subject descriptions become obsolescent. The issues, tensions, and compromises involved are introduced. Drawing on the work of Robert Fairthorne and others, an explanation of the unavoidable obsolescence of assigned subject headings is presented. The discussion relates to libraries, but the same issues arise in any context in which subject description is expected to remain useful for an extended period of time. © 2012, Emerald Group Publishing Limited