With information about the serials holdings of over 100 UK research libraries SUNCAT is the ideal tool for providing an overview of serials holdings across the UK. Currently, however, it is only possible to search the web interface title by title, which makes the comparison, of any significant collection of serials, a resource intensive exercise. Therefore, to enable libraries to easily conduct a more comprehensive comparison we have developed a new Serials Holdings Comparison service.

The service enables libraries to submit a file of ISSNs for comparison purposes. The results produced can help with decision making around collection management tasks, such as cancelling or renewing subscriptions, moving titles into storage, or deselecting lower use material.

The service consists of a simple interface where a library can upload a CSV file of ISSNs. They can then:

• Choose to run the comparison against all 103 libraries on SUNCAT, or against a particular selection of libraries
• Choose to compare against print only holdings, or against print and electronic holdings

The submission process is very straightforward and a validation stage will highlight any missing or invalid ISSNs in the file, which may be useful beyond the scope of the comparison.

There are a number of different outputs, including:

Graph view: a visual overview or snapshot of the level of holdings for titles across the selected libraries

List view: this displays the total number of holding libraries for each ISSN and lists each holding library and its summary holding statement. The list can be ordered by number of holding libraries and can be filtered to show those titles submitted which are held in a small or, alternatively, a large number of libraries and by those titles marked for UKRR retention.

CSV file: a detailed report of all the libraries holding each title, an indication if the holdings are print or electronic, their summary holdings statements and an indication of whether a title is marked for UKRR retention.

We have completed some initial testing on the service with a number of our contributing libraries and have subsequently made some improvements to the service. We would now like to open up the test service to a wider group of libraries to gather further feedback before we make the service available to all. If you have a task or project, with which you think the service might assist, and would be willing to provide some feedback on the process and the service in general, then please contact us at suncat@ed.ac.uk as soon as possible. We will be happy to arrange a short demo of the service and for access to the test site.

If you have any questions about the new service please also contact us at suncat@ed.ac.uk, we look forward to hearing from you!

SUNCAT is the Serials Union Catalogue for the UK. Visit the service at http://www.suncat.ac.uk.

SUNCAT is based on the bibliographic serials records of a Contributing Library and the associated holdings.  In order to create a clean search result, the records for the same title are put into one set, with the holdings for all records visible at the point of display attached to the best bibliographic record (preferred record). This means that the user, having located a journal in the database, is shown a coherent display of all the holdings information for the contributing libraries.

Building a union catalogue therefore involves establishing which of the submitted records from Contributing Libraries should be matched as they represent the same entity.  The outcome is the creation of a large number of sets, with each set containing all the matched bibliographic records submitted by the Contributing Libraries, along with the associated holdings information. Where there is no match of a record with any other submitted record, the set will contain one record.

Updating a union catalogue involves running a complex set of processes.  The key steps are the following:

1.    For each incoming record the identification of records already in the database for possible matching with each incoming record.  Possible matched records are copied into the ‘Candidate Pool’. The selection of candidates involves utilising 3 direct indexes (LCCN, ISSN/ISBN and a keyword index (normalised index)

2.    Running of processes to ascertain with which records (if any) in the candidate pool the incoming record matches.   This involves running a matching algorithm which compares key elements (title, ISSN etc.) in the incoming record with each record in the candidate pool and assigning numerical values depending on whether or not there is a match between the data elements.  The values for each element are totalled and, when the pre-determined threshold  value is reached, a match is declared.   The matched records are held in the ‘Matched documents buffer’. More information on the matching algorithm is provided here. 

3.    Recording the details of matched records held in the ‘Matched documents buffer’ on the incoming record and the record(s) already in the database.  This is done by each record in the database having an associated table (z120) and this contains information such as the number of records with which it has matched and the system numbers for these matched records.

EDINA had requested some improvements to the processes used to carry out the above and these improvements were included in the Aleph version 20 upgrade carried out in late 2013.  The specific improvements are:

·         New Candidates Pool Size Parameter.  The allowed values are now between 100 and 500.  This has been initially set at 250 meaning that if 250 or fewer records are identified, the process moves onto the matching stage.  If more than 250 candidates are identified the software deems the incoming record not to match and it therefore becomes a single record set.  

·       Candidate Pool Common titles. A new routine has been added to help reduce the number of candidate titles.  All candidate titles are compared with a list of common titles and if there is a match the candidate title is excluded from the candidate pool.

·         Matched Documents Buffer. The size of this has been increased from 100 to 500.  This expansion is necessary as the number of SUNCAT Contributing Libraries increases.

As part of the ongoing SUNCAT software redevelopment, work has already begun on the design of a new, improved matching algorithm.  More information on the approach being taken will be given in a future blog posting.