Policy: Overlay in Alma


This document describes policy and methods for replacing (that is, overlaying) individual bibliographic records in Alma with records exported from OCLC Connexion client or brought into the Network Zone (NZ) from daily OCLC loads. This policy does not apply to batchloads.

The objective is to avoid unintended overlays and duplicates in the Alliance shared environment. Since there is still much to be learned about Alma and the Network Zone, you should also view the Overlay in Alma Procedures page for carrying out this work.


The NZ contains fully cataloged bibs representing the holdings of all Alliance libraries. The NZ may also contain less than full records such as brief records with orders attached.

It is Alliance policy that newly cataloged titles go in the NZ in order to facilitate cooperative collection development and collaborative technical services. Brief records for new orders also go in the NZ, but brief records that existed in Millennium were migrated to each library’s Institution Zone (IZ).

The following steps must be done even if the cataloger is allowing the daily OCLC loads to bring the bib record into the NZ, rather than exporting from Connexion.

Catalogers must search for a title in both the IZ and the NZ. The title may be only in the IZ, only in the NZ, or in both. Records only in the IZ need to be moved to the NZ (“Share with Network”) for overlay to occur successfully.

Bibliographic overlay in Alma is always done by OCLC number. Catalogers must ensure that the incoming Connexion record and the existing Network Zone record have the same OCLC number. It must be in field 035 and preceded by “(OCoLC)”, e.g.: 035 __ $$a (OCoLC)777212655.

The OCLC number in an Alma record may be 1) correct (matching), 2) lacking, or 3) different than the number in the record you intend to use for cataloging. Procedures for each scenario are given below. If the OCLC number in the Network Zone record is not the one you intend to use, do NOT overlay the record. Until 2015, when all Alliance libraries have migrated, there will be bibs in the NZ without holdings that may be needed later and these records should not be overlaid.

Key points to remember (in this order!):

  • Ensure that the correct OCLC number is in the Alma record
  • Share with Network (if not already there)
  • Then Alma is prepared to accept the the record, via Connexion export or daily OCLC loads.

See the procedures page for more details.


Software: Alma

Current phase: Phase 5: Approved

Written by: Collaborative Technical Services Team

Approved by: Collaborative Technical Services Team on 12/19/2014, 3/21/2014, 10/14/2013

Last updated: 4/19/2016

Nature of last update: minor update

Document History:

  • Policy has undergone multiple revisions by the Collaborative Technical Services Team.
  • When policy was migrated to Alliance website it was split into a policy page and a procedures page. This was recommended in the originally policy and carried out on 4/19/2016.