Doing Research at the Library of Congress
IIA. Three Basic Principles of Library of Congress Subject Headings
b. Scope-match level of coverage
The principle of scope-match coverage refers to the level of depth
at which books are indexed. As a rule, catalogers try to assign
only as many
headings to a work as are necessary to sum up the subject of the work as
a
whole. In other words, they will not usually assign headings for each individual
chapter or section of a book. The result is that most catalog records
receive from two to five headings rather than ten or fifteen, and many books
receive fewer than three. For example, a book covering Oranges, Grapefruit,
and Tangerine will receive these three headings; but if it also
covers
Lemon, Limes, and Tangelo it
will receive the one heading Citrus rather
than six individual terms at the chapter-level. The level of depth aimed for
is the smallest number of headings covering the book as a whole. (Note
that chapter titles are sometimes transcribed as keywords within the "note"
fields of catalog records; but this level of indexing is not covered by the
standardized terms of the subject headings system.)
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