Faceted vocabularies

That was the topic discussed recently by OCLC Research Library Partners metadata managers, initiated by John Riemer of UCLA. Originally entitled “trend away from pre-coordinated subject headings”, this topic was inspired by the National Library of Medicine’s discontinuing distribution of cataloging data with pre-coordinated subject strings in 2015, replacing them with separate facets for topic, place and form. Our discussions focused on Faceted Application of Subject Terminology (FAST), originally developed by OCLC as a happy medium between totally-uncontrolled keywords at one end of the spectrum and difficult-to-learn and -apply pre-coordinated subject strings at the other end. The British Library and others are considering moving away from pre-coordination to FAST. The payoff for adhering to a pre-coordination approach has been declining and its upkeep is increasingly a challenge. At the same time the perceived benefits of an approach like FAST are rising.

In John’s recent article, “The Gravitational Pull Away from Pre-Coordinated Subject Headings, published in the May/June 2016 issue of Technicalities, he concluded that the library community would need to decide whether changing to FAST “warrants a strenuous objection or little more than a ripple of concern.”

Among OCLC Research Library Partners, adoption of FAST has ranged from applying it to “everything” to only digital collections, reducing backlogs, theses and specific projects. We already have “hybrid” databases that include both LC Subject Headings (LCSH) and FAST, and libraries vary in their treatments of them. Some strip out FAST headings from incoming records and others retain them, but do not assign them to new records. Some assign LCSH headings but then convert them to FAST using the FAST Converter (pictured above). Some replace uncontrolled keywords with FAST headings. As WorldCat is the result of collaborative efforts among thousands of libraries around the world, those who use FAST headings in their local catalog records will often obtain records that have had LCSH added, and those that use only LCSH can obtain the FAST headings that OCLC generates from the LCSH headings.

FAST is most attractive for descriptions that would not otherwise receive subject treatment at all, or only carry uncontrolled key terms. But switching from LC Subject Headings to FAST or other faceted subject headings for all materials has trade-offs.

Among the reasons for using faceted vocabularies:

• Users don’t need to know order of terms
• Terms are easier to apply
• More people without specialized subject expertise can apply them, including students and researchers, reducing cataloging costs
• More records get subject indexed
• Subfielding ambiguities are avoided
• Terms are more specific than vendors’ broad headings such as BISAC (Book Industry Systems Advisory Committee)
• They provide an easy transition to a linked data environment, as each FAST heading has a unique identifier

Among the reasons why libraries are reluctant to move away from pre-coordinated subject headings and to adopt FAST at this time:

• Lose the context, cross references and scope notes offered by pre-coordinated subject headings
• Retrieve more irrelevant search results
• Chronological and geographical facets may not apply to all topics equally
• Not supported in metadata creation tools
• Not supported in discovery systems and browse displays
• Can’t hyperlink multiple FAST terms for “more like this”

Some libraries are conducting cost-benefit analyses of switching to FAST. The high cost of training staff to apply LC Subject Headings, which also means these specialists cannot be deployed in other areas, is a driver for administrators to consider FAST. Training staff who already know LCSH to use FAST instead is extremely easy – Cornell reports such training takes a mere ten minutes. (Cornell has created a cheat sheet for applying FAST, “FAST Headings for Cataloging”.) But some have reported that people without any library training can easily apply FAST. Brown provides an input form for its institutional repository that links to FAST so that researchers can apply the appropriate terms to their papers. The assignFAST tool offers “autosuggest” of FAST subjects. Maintenance costs should also be reduced—as terms change over time, the persistent identifier associated with each FAST term should always point to the most current version.

Increased usage of FAST will depend on vendors’ adoption and support, or the willingness of libraries to customize their interfaces until vendor support is available. For example, libraries would need to include their FAST terms in their browse index so that they appear in browse displays. Users would need the ability to select multiple facets at a time, or serially, to retrieve results that are “more like this”.

FAST’s future technical and editorial support is a key concern. Initially generating FAST headings from LCSH was a pragmatic way to obtain millions of headings easily, but how sustainable would it be in the future to continue to have FAST “yoked” to LCSH? Shouldn’t it be possible to create new FAST terms independent of LCSH? It was posited that perhaps the Program for Cooperative Cataloging’s Subject Authority Cooperative Program (SACO) could consider proposals for new FAST terms as it does now for new LCSH proposals.