Matching Algorithm

Collection Group Designation

CGD	Shareable	Retention Commitment	Notes
Committed	Shareable	Yes	CGD not changed by Matching Algorithm. These are items purchased via cooperative collection agreements, identified by the vendor. Do not expect that two items will match and both have the CGD of Committed. If two items match and are submitted as Committed, both will retain the Committed designation. If a Committed item matches a Shared item, both will retain their designations as Committed and Shared.
Shared	Shareable	Yes
Open	Shareable	No	When submitted as Open, not changed by Matching Algorithm. It is not expected that items will be submitted as Open going forward, but it has been done in the past.
Uncommittable	Shareable	No	CGD not changed by Matching Algorithm.
Private	Not shareable	No	CGD not changed by Matching Algorithm.

Ongoing Matching Algorithm

The ongoing matching algorithm is run on items with the same Material Type when:

new items are accessioned to SCSB with a CGD of “Shared”
existing items are updated to a CGD of “Shared” and in the “cgd_no_protection” folder

The new/updated item is compared to all the existing items in the database with a CGD of Shared or Committed.

When two items match, the item that was accessioned earlier will retain the Shared status, while the newer item will be bumped to Open.

Items are considered a “match” when two of the following points match:

Matching copies from a single institution are not compared. It is up to the submitting institutions to only submit one copy of matching items to SCSB as “Shared,” and the rest as “Open.”
When two items have a single number match but having different bib levels; one is a monograph and the other a serial. That is when the material type does not match, the matching algorithm is not applied.
When the CGD of an item is changed manually to Shared using the SCSB UI, the matching algorithm is not run on the item. This means that there could be two items with the Shared CGD.

The following reports are generated after each run of the matching algorithm:

Example file name: MatchingSummaryReport-27Jul2021080127.csv
Columns: Institution, Total Bibs, Total Items, Shared Items Before Matching, Shared Items After Matching, Difference of Shared Items, Open Items Before Matching, Open Items After Matching, Difference of Open Items
Rows:PUL, CUL, NYPL, HL
Example data:

Includes items that were changed from Shared to Open for Serial and MVM material types
All items that match are changed from Shared to Open
Example file name: MatchingSerialMvmReport-27Jul2021080114.csv
Columns: OwningInstitutionId, Title, Summary Holdings, Volume Part Year, Use Restriction, BibId, OwningInstitutionBibId, Barcode
Example data:

Items that match on only one number and not the first four words of the normalized title will be included in this report. Previously, these items were considered a match and the CGD was affected, but as of v4.3 (July 2021), they are not considered matched.

Columns: OwningInstitution, BibId, OwningInstitutionBibId, MaterialType, OCLCNumber, ISBN, ISSN, LCCN, Title1, Title2, Title3, Title4, Title5, Title6, Title7, Title8, Title9, Title10, Title11, Title12, Title13, Title14, Title15, Title16, Title17, Title18, Title19
Example data:

A report will be created if any item’s CGD is changed by the matching algorithm.
All the items with a change to the CGD will be included in the report.
The report will be written to the SCSB AWS S3 bucket.
The report is institution specific and will be put into the corresponding directory for that report and institution.
The directory in the S3 bucket will be:
reports/cgd-round-trip/<institution>/
The name of the report will be CGD_RoundTripReport_<timestamp>.csv
ex: CGD_RoundTripReport_20210322_185905.csv
Columns: Item Barcode, Old CGD, CGD, Date of Action
Example data:

The matching algorithm will no longer consider Use Restrictions as of v4.3 (July 2021) and beyond.

The technical Documentation for matching algorithm - Technical Documentation for Matching Algorithm