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Cooperative quality

WorldCat represents a long-lasting collaboration among libraries, material providers and OCLC. Together, we maintain a system for quality bibliographic metadata creation and management. This community’s continuous maintenance and improvement of WorldCat records, following the guidelines in Bibliographic Formats and Standards, is central to our commitment to each other. Quality bibliographic data forms the foundation for successful discovery and sharing of library resources.

Learn more about WorldCat data standards

Sources of WorldCat records (as of April 2017)


OCLC member libraries 74.47%

National libraries 20.10%

Library of Congress 2.62%

Vendors/publishers 2.81%

Tommy Nixon [photo]

“Breadth of collections…”

“I use WorldCat on FirstSearch 10–15 times a day at least, sometimes more. I couldn't do my job without WorldCat on FirstSearch. The breadth of collections is unparalleled.”

Tommy Nixon
MLIS Subject Librarian for Classics, Dramatic Art, & English/Comparative Literature
Davis Library, University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States

Libraries of all types contribute to and enhance WorldCat.

Libraries of all types from all over the world contribute to the quantity and quality of WorldCat records, so the records shared here represent many diverse interests. Every library, museum or archive that contributes metadata to WorldCat, including through a group, receives the membership benefits of the OCLC cooperative. OCLC members range from tiny public libraries in rural areas to major academic libraries spread across multiple buildings in a large city, from specialty libraries with depth in one specific topic to national libraries that encompass a whole nation’s cultural achievements. Each has something unique to share with the world through WorldCat.

Number of WorldCat records enhanced by member libraries:

Last year:1,503,531

(July 2015–June 2016)

Last month:94,824

(April 2017)

Peter Sidorko [photo]

“Global library cooperation…”

“Encompassing libraries from all sectors, of all sizes and at various stages of development, WorldCat epitomizes global library collaboration, crossing borders, languages and cultures to provide an unrivalled, unifying bibliographic platform.”

Peter Sidorko
OCLC Global Council President
University Librarian, The University of Hong Kong
Pokfulam, Hong Kong

National libraries

National libraries all over the world share their collections through WorldCat. This allows libraries everywhere to connect people with information about many cultures and national identities.


National Library of Australia

  • WH: 5,750,866
  • OR: 2,189,382


National Library Service

  • WH: 23,955
  • OR: 5,454


The Botswana National Library Service

  • WH: 43,993


Biblioteca Nacional de Chile

  • WH: 13,827
  • OR: 10,423


The National Library of China

  • WH: 4,231,090
  • OR: 2,604,336

Czech Republic

National Library of the Czech Republic

  • WH: 867,369
  • OR: 784,111


Det Kongelige Bibliotek

  • WH: 2,590,720
  • OR: 2

Danmarks Pædagogiske Bibliotek

  • WH: 469,671
  • OR: 222,427


The National Library of Finland

  • WH: 753,525
  • OR: 717,640


Bibliothèque nationale de France

  • WH: 18,920,092
  • OR: 18,151,940


Deutsche Nationalbibliothek

  • WH: 15,654,201
  • OR: 11,197,525


National Séchényi Library

  • WH: 16,355
  • OR: 16,357


The National Library of Ireland

  • WH: 156,458
  • OR: 37,075


The National Library of Israel

  • WH: 2,369,507
  • OR: 1,624,719


The National Library of Jamaica

  • WH: 36,737
  • OR: 23,455


National Diet Library of Japan

  • WH: 5,536,340
  • OR: 5,099,772


Lebanese National Library

  • WH: 43


Lesotho National Library and Archives

  • WH: 1,932


Liechtenstein State Library

  • WH: 298,877


National Library of Lithuania

  • WH: 203


Perpustakaan Negara Malaysia

  • WH: 1,947,076
  • OR: 349,886


Biblioteca Nacional de Mexico

  • WH: 428,675
  • OR: 322,152


The National Library of Namibia

  • WH: 33,629


Koninklijke Bibliotheek

  • WH: 40,244,079

New Zealand

The National Library of New Zealand

  • WH: 1,913,991
  • OR: 937,662



  • WH: 0
  • OR: 474


Biblioteka Narodowa

  • WH: 2,760,983
  • OR: 2,047,337

Russian Federation

The National Library of Russia

  • WH: 4,061

Russian State Library

  • WH: 158


National Library Board

  • WH: 2,027,761
  • OR: 448,947

South Africa

The National Library of South Africa

  • WH: 274,250
  • OR: 176,894


Biblioteca Nacional

  • WH: 4,647,646
  • OR: 4,336,225


The Swaziland National Library Service

  • WH: 2,507
  • OR: 2


Kungl. Biblioteket

  • WH: 9,030,537
  • OR: 8,310,514


The Swiss National Library

  • WH: 1,264,698
  • OR: 678,176


National Central Library

  • WH: 1,036,337
  • OR: 498,500


Milli Kütüphane

  • WH: 496

United Kingdom

The British Library

  • WH: 20,669,068
  • OR: 9,819,192

The National Library of Scotland

  • WH: 5,096,627
  • OR: 1,855,280

The National Library of Wales

  • WH: 258,924
  • OR: 47,815

United States

Library of Congress

  • WH: 12,960,008
  • OR: 12,324,675

National Agricultural Library

  • WH: 988,129
  • OR: 413,542

National Library of Education

  • WH: 78,530
  • OR: 19,978

National Library of Medicine

  • WH: 3,700,391
  • OR: 3,366,778

WH = Number of WorldCat holdings     OR = Number of original records

Data current as of March 2017

Academic libraries

Academic libraries support students and faculty with specialized research on a wide variety of topics. They contribute records to WorldCat for these resources and their unique holdings, such as dissertations, theses, published research papers and often the data sets that support that research.

Search in one place for resources worldwide.

interior of the library at John Cabot University [photo]

“The power of WorldCat as an information retrieval tool is enormous.”

Elisabetta Morani, Head Librarian
John Cabot University, Italy

Read John Cabot’s story

Improve the quality of your online catalog.

woman using the library at Biblical Theological Seminary [photo]

“The students appreciate that the catalog is available in Korean [through the WorldCat Discovery interface]. I've seen a number of them with it set to that.”

Lydia Putnam, Technical Services Manager
Biblical Theological Seminary, United States

Read the seminary’s story

Public libraries

Public libraries form the centerpiece of their communities by providing a wide variety of services and by archiving local history and genealogical resources. By cataloging their materials in WorldCat, public libraries connect people around the world with resources for job searches, school science projects, book clubs, cooking and many other topics.

Satisfy a wider range of needs through worldwide resource sharing.

exterior of Stow-Munroe Falls Public Library [photo]

“The breadth and depth of what's available through the OCLC resource-sharing network is an invaluable source of materials for our community.”

Diana Parker, Interlibrary Loan Coordinator
Stow-Munroe Falls Public Library, United States

Read Stow-Munroe Falls’ story

Pull your archives out of the basement and share them with the world.

Logo for Picture South Perth [photo]

“...our users ... can now browse the collections at their leisure, at any time of day, from any location...”

Farah Kabbani, Local History Librarian
South Perth Library, Australia

Read South Perth’s story

Special libraries

Special libraries support distinct organizations, such as a government office, church, corporation, hospital, museum or research center. These libraries contribute incredibly deep collections to WorldCat on very specific topics that are invaluable to researchers.

Move from cataloging to curating for your users.

people in Pritzker Military Museum and Library [photo]

“We're putting VIAF numbers into Wikipedia and helping to build those connections between Wikipedia and WorldCat.”

Theresa Embrey, Chief Librarian
Pritzker Military Museum & Library, United States

Read Pritzker’s story

Facilitate research through group catalogs.

Painting: The Return to Amsterdam of the Second Expedition to the East Indies, Hendrik Cornelisz Vroom, 1599, courtesy of the Rijksmuseum [photo]

“The benefit of this move to WorldCat is how scalable it is.”

Geert-Jan Koot, Head
Rijksmuseum Research Library, Netherlands

Read the Rijksmuseum’s story

Libraries improve WorldCat through cooperative management.

The cooperative nature of WorldCat lets all libraries participate in the continuing improvement of WorldCat bibliographic records and collections. Not only can librarians contribute, edit and export WorldCat records, but most can also make changes to core bibliographic data in WorldCat master records that other libraries can localize for their own catalogs. Libraries may have different levels of authorization based on their participation in WorldCat.

Catalogers can add records to the WorldCat bibliographic catalog in whatever authorized cataloging guideline or rules their institutions use, including RDA, AACR2 and specialized community standards. They can export records from WorldCat in various MARC and Dublin Core formats to use in library management systems and other systems.

Sharing materials across borders in Europe

Carol Bream [photo]

“Searching for information…”

“The European Commission is a highly secure environment, which makes it really difficult to get data across borders... . Therefore, we decided to put our library data on WorldCat, so it’s available not only for external users searching for information on Europe, but also for our own staff.”

Carol Bream
Advisor on the Future of Libraries (Retired)
European Commission Central Library
Brussels, Brussels-Capital Region, Belgium

OCLC staff improve WorldCat every day.

Whether reviewing records uploaded in batch, merging duplicate records or correcting reported errors, OCLC’s staff members help make WorldCat a valuable and unique resource for libraries worldwide.

Due to the global nature of WorldCat, we frequently address challenges around cultural inclusion, diversity and complexity. We help libraries contribute data to WorldCat that's in non-Latin script, that follows very different cataloging and publishing traditions or that sometimes treads on sensitive geo-political ground.

Our global data specialists work with libraries to review large batches of records before contributing them to WorldCat. By cleaning this data first, we increase the chances of matching new data to existing master records. Often, the data that libraries access in WorldCat are better than the data they provided.

Enhancing the visibility of Basque culture

Jay Weitz [photo]

“Expect more…”

“Underlying it all, though, is the sense that our users all over the world expect more of OCLC because of who and what we are. My colleagues and I get that and keep it foremost in our minds in everything we do.”

Jay Weitz
Senior Consulting Database Specialist, Data Services and WorldCat Quality Management
Dublin, Ohio, United States

Bemal Rajapatirana [photo]

“Transform individuals…”

“At our core, we are data specialists committed to sharing knowledge and information through libraries so that they continue to transform individuals, societies and humanity.”

Bemal Rajapatirana
Manager, Metadata
Leiden, South Holland, Netherlands

WorldCat Quality Team

Our WorldCat Quality Team is dedicated to improving the WorldCat bibliographic catalog, knowledge base and registry. Among them, this team has more than 265 years of experience with OCLC. Our 12 catalogers who focus on bibliographic and authority records—eight of whom hold an MLS degree—create and enhance WorldCat records both by hand and through automated, monitored systems. From July 2015–June 2016, the WorldCat Quality Team enhanced more than 80 million WorldCat records.

Shanna Griffith [photo]

“Improve the quality…”

“I love being a part of the WorldCat Quality Team at OCLC. We understand how important it is to our member libraries that the items in their collection are easily discovered by their patrons. As a membership cooperative, we work with our member libraries to improve the quality of existing cataloging data in WorldCat to make that possible.”

Shanna Griffith
Database Specialist II, Data Services and WorldCat Quality Management
Dublin, Ohio, United States

WorldCat Quality Team members actively participate in the Program for Cooperative Cataloging (PCC) and professional organizations, such as the American Library Association (ALA), Online Audiovisual Catalogers (OLAC) and Music OCLC Users Group (MOUG) by serving on many committees, task forces and boards. We’re especially active in ALA’s Association for Library Collections and Technical Services (ALCTS), where team members have served as President of ALCTS and Chair of the ALCTS Cataloging and Classification Section (now called CaMMS).

Enhancements by request

The WorldCat Quality Team reviews every WorldCat record change request submitted and determines the best action to take. Sometimes they change only one record, and sometimes they find and change related WorldCat records with similar errors. The team also proactively changes records in WorldCat to reflect policy updates, such as changes to subject headings or provider-neutral coding for electronic resources.

Request a WorldCat record quality enhancement

Number of bibliographic records enhanced by the WorldCat Quality Team:80,806,835

Enhancement requests received:108,677

(July 2015–June 2016)

Only the best version of a record

The WorldCat Quality Team maintains and monitors Duplicate Detection and Resolution (DDR) software, which processes WorldCat records to identify and merge duplicates. DDR software scans existing WorldCat records and identifies duplicates. This automated effort—backed by experienced quality control catalogers—improves the value of WorldCat by merging duplicate records. In addition to the software, the WorldCat Quality Team identifies and merges duplicates manually when appropriate. The team also relies on OCLC members to report duplicate records that should be merged and records that were merged inappropriately.

Learn more about cataloging defensively with DDR

Records merged annually by the WorldCat Quality Team:668,074

(July 2015–June 2016)

Duplicates removed by DDR software since May 2009:24,818,615

(as of April 2017)

Authority files to simplify cataloging

OCLC houses and maintains the VIAF (Virtual International Authority File) service, which aggregates the world’s major name authority files. More than 50 organizations from more than 30 countries, including many national libraries, contribute their authority files to VIAF, which then matches and links the records into a merged “super” authority record. This allows information about a single person, for example, to be discoverable no matter how that person’s name is represented in any language or character set.

Learn more about VIAF

OCLC also plays a prominent role in other worldwide authority file systems, such as ISNI (International Standard Name Identifier), the ISO-certified standard for identifying the creator of a work. OCLC hosts ISNI, and the ISNI International Agency maintains the authority files. This information feeds into VIAF and other authority databases to give a full picture of a creator across the web.

Catalogers use these authority records and others, such as the Library of Congress’s Names and Subject Authority Files, US National Library of Medicine’s Medical Subject Headings (MeSH), Koninklijke Bibliotheek’s NTA Names (Nederlandse Thesaurus van Auteursnamen), and Deutsche Nationalbibliothek’s Integrated Authority File (GND) in their regular cataloging workflows. They then add bibliographic records with standard names, subject headings and other information to WorldCat, enriching the value of WorldCat to libraries around the world. OCLC provides tools for displaying these authority files to catalogers and for linking the headings in bibliographic records to them. OCLC is also a node for the Library of Congress’s Name Authority File, so changes that catalogers make to this file within OCLC systems are automatically updated daily in the Library of Congress files.

Learn more about authority files

Authority records created by WorldCat Quality Team for Library of Congress Name Authority File:233

Authority records enhanced:455

(July 2015–June 2016)

Geoff Payne [photo]

“Attractive to the university…”

“Being able to provide researcher profiles in a way that is automatically updated by doing periodic canned searches is very attractive to academics. It's also attractive to the university, because rather than having a static research profile that goes out of date, it can be done dynamically.”

Geoff Payne
Deputy Director Strategy and Planning
La Trobe University Library
Melbourne, Victoria, Australia

Partners support WorldCat and help libraries.

The scale of WorldCat and the non-profit nature of the OCLC cooperative allows member libraries to work as a group with other organizations to improve the flow of information that helps users find and access resources. These partnerships help get new library resources in front of users faster.

To ensure that libraries always have access to the resources they need, OCLC makes formal agreements with certain partners. These agreements allow the partners to provide services to a member library using WorldCat data that the library provides. Each agreement varies based on the services offered by the partner organization.

See partners authorized to catalog in WorldCat

Authorize partners to manage your WorldCat data

The records libraries need as quickly as possible

OCLC and partners make records for soon-to-be-published items available as quickly as possible so that libraries can share these resources with users. The Library of Congress and other national cataloging agencies provide publishers with cataloging-in-publication (CIP) records to print in the book prior to publication. These CIP records are also added to WorldCat in an effort to share pre-publication information about the resource.

The CIP upgrade program enhances these minimal WorldCat master records, which eliminates the need for each library to upgrade their records individually. Library material vendors, including GOBI Library Solutions from EBSCO, Ingram, Quality Books, Inc. and The Donohue Group, supply upgraded records that overlay existing CIP records in WorldCat as soon as the full bibliographic information is available. Also, Follett Titlewave works online to upgrade CIP records.

Download CIP upgrade specifications

Strength in numbers

OCLC also works with Research Libraries UK (RLUK), a group of 37 leading research libraries in the UK and Ireland, to correctly contribute these collections to WorldCat and then analyze the data to help RLUK make strategic decisions about shared print collection management and resource discovery. WorldCat brings a unique, system-wide perspective to RLUK’s collections, which allows the libraries to collaborate on a deeper level. RLUK and OCLC Research have documented results of this partnership in a final report, Strength in Numbers: The Research Libraries UK (RLUK) Collective Collection.

Read RLUK blog posts about the project

Stella Butler [photo]

“Deliver better research impact…”

“Using a unique, global library resource like WorldCat is a perfect fit for RLUK. We will have a much more precise understanding of our collective assets and where we can act to deliver better research impact and more effective management for their collections.”

Stella Butler
Former Chair, Research Libraries UK
University Librarian and Keeper of the Brotherton Collection, University of Leeds
Leeds, Yorkshire, England

Making WorldCat data work for libraries

OCLC works on behalf of libraries to make high-quality WorldCat data available for libraries and partners all over the world to share and reuse across many systems, sites and applications. To ensure that WorldCat remains valuable and sustainable, the OCLC Board of Trustees has collaborated with member libraries to develop several policies and guidelines that outline a code of good practice based on shared values, trust and reciprocity. The OCLC Global Council has asked members to follow the community norms set forth in WorldCat Rights and Responsibilities for the OCLC Cooperative when using and transferring individual WorldCat records and aggregated sets of those records.

WorldCat Rights and Responsibilities for the OCLC Cooperative

Using the data

OCLC strives to make WorldCat records accessible and valuable to libraries and researchers. While OCLC makes a copyright claim on WorldCat as a compilation, we make no copyright claim on the individual records in WorldCat. To clarify the rights to the information contained in specific records, the OCLC membership endorses the Open Data Commons Attribution (ODC-BY) license. OCLC has implemented an ODC-BY license notice for its own projects. This license gives WorldCat users a firm foundation upon which to build new applications, perform analyses, create new tools and otherwise build new things using their library information.

Learn more about data licensing