What is Central Index?
OCLC negotiates with content providers and publishers, such as EBSCO, Gale, and ProQuest, to include their bibliographic records for indexing in WorldCat. The article and book titles indexed in Central Index show up in Melvyl search results.
What’s the value of Central Index?
Central Index affects what users see in search results. Central Index delivers an enhanced user experience because search results include articles. Articles display in search results only when the associated Central Index database is activated.
Not all articles will display UC library holdings even though users may have access to the online or print article. Why is this? UC libraries set holdings in Melvyl at the journal title level. Articles in search results inherit the UC libraries holdings from the journal title record. Holdings may not display because:
- UC libraries may not own all journal titles in a database.
- UC libraries may not own the full run of a journal title (i.e., gaps in holdings.)
- UC libraries may not have cataloged the title.
What’s in Central Index?
Central Index includes abstracting and indexing (A&I) databases such as ArticleFirst and publisher databases such as Wiley Online Journals. OCLC has not been consistent in their characterization of what’s included in the WorldCat Central Index. For UC purposes, CDL considers the databases in WorldCat to be the “Central Index”. Databases are the part of Central Index that CDL can turn on or off in Melvyl search results.
How is Central Index managed in Melvyl?
Melvyl began using the OCLC WorldCat Central Index in August 2012 following an assessment report by a UC Libraries’ Heads of Public Service (HOPS) subgroup, and approval by the Melvyl Advisory Group.
CDL manages Central Index for Melvyl — this includes both the individual campus versions of Melvyl and the union version of Melvyl, and CDL activates the Central Index databases included in Melvyl searches.
How does Central Index work in Melvyl?
- UC libraries must license a database before it can be activated in Central Index.
- CDL adds new databases monthly, after OCLC’s monthly installation of enhancements and bug fixes has been completed and verified.
- The Central Index databases included in Melvyl search results are selected based on the Melvyl Central Index Procedures.
- The default is to show all activated Central Index databases in search results. Melvyl users may search these Central Index databases separately or in combination using Advanced Search. Users can see the list of databases activated in search results facets.
- While articles display in search results, Central Index does not provide links to those articles. The UC-eLinks icon displays in the detailed records so users can determine if they have access to an electronic version of the article, and if so, to click-thru to access the article online.
Limitations of Central Index
- Central Index includes only a small subset of all UC-licensed databases — a limitation of all discovery systems; notably, many science databases are not yet available.
- Some vendors make their data available via remote access only (Z39.50); CDL does not activate these databases due to poor response time, which slows overall search results.
- Some vendors do not provide their metadata to OCLC and other discovery platforms. The CDL licensing team advocates for vendors to comply with the NISO Open Discovery Initiative (standard approved & published June 2014)
- The OCLC licensing process is slow: It takes about 12-18 months from the time OCLC approaches a publisher until the time the records are available in Central Index.
How to remove all databases from search results
On the Advanced Search screen, you can limit your searches to specific databases to improve the accuracy of your search results. To clear all databases (which are ‘on’ by default)…
- Scroll to the bottom of the screen & click the Select All in Group button. This should un-check all the databases listed on the screen.
- Then select the specific databases you want to search and click the Save Changes button at the top of the list of databases. You should see an ‘on screen’ confirmation of the databases you are now searching.