An aspect of my OPAC to check:

"A topic which has seldom been addressed in the literature is examined by Gregory Wool. Because librarians have relinquished their control over the traditional catalog’s filing rules by meekly accepting the limitations imposed by programmers and designers of OPACs, the result has been an accidental (or, unintended) deregulation of standard arrangements of subject headings in the indexes. Wool illustrates in particular how the Library of Congress Filing Rules, which arranges entries differently according to the punctuation that is present (e.g., commas for inverted headings, parentheses for qualified headings, etc.), takes advantage of the highly developed syntax and semantic features of the LCSH and result in logical groups that can benefit the searcher. These structured but perceivably helpful collocations are lost, however, in most online catalogs that simply arrange LCSH strings in a word-by-word fashion, causing Wool to wonder if LC and the library community as a whole have virtually abandoned their faith in a precoordinated controlled vocabulary. "

from The LCSH Century