By definition, authority control demands a single “authority.” LTI’s services provide the highest quality authority control available to libraries today. Using a local system’s authority control module will undermine the advanced algorithms and tables that were used to authorize the library’s database.
Such software modules rely on matching and updating bibliographic headings based on the presence of the “old” heading as a cross-reference (4XX) in an authority record – a limitation, which can both miss needed revisions and introduce problems. LC frequently does not carry over the "old" heading, and even when it does there may be other issues in linking because of variations in capitalization, spacing, or punctuation occurring, in either catalog record headings or in LC authority records. Dozens of such errors in authority records are reported by LTI to LC each week
More problematic than changes that are missed are revisions that should not be made at all. Currently, we block over 201,000 headings in authority records (mostly 4XX fields) from linking to any heading because of the likelihood of introducing an error. Other heading changes are limited to only certain types of linkages, perhaps additional data must be present, or there must be an absolutely exact match, before the link is allowed.
LTI users report strange things when they “turn on” their local system’s authority control module. For example, the library may find a disproportionate number of headings tagged as subjects but that are in fact titles or series. While a series may on rare occasions be used as a subject, it is uncommon, and rarely permissible along with the presence of form ($v), topical ($x), period ($y), or geographic ($z) subdivisions. If these rules are ignored,
$aRomance languages $x Modality
can be converted to:
$aAmerican university studies.$nSeries II,$pRomance languages$xModality.
because the authority record for "American university studies. Series II. Romance languages," has a 430 variant title of "Romance languages".
LTI's processing protects against this type of incorrect tag level change and, if not linked correctly by our code or editors, at worst, the above headings appear in the unlinked headings list.
Such problems appear to be present to some degree in all databases where the library uses an authority control module made available by its ILS vendor, unless substantial staff time is invested in reviewing every such change. Regardless of local system, LTI strongly advises that ILS modules making automatic changes based on authority records be disabled.