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OPACs and Bibliographic Control

Learning Objectives
• Define library catalog.
• Define Online Public Access Catalog (OPAC) and provide examples.
• Define union catalog.
• Define WorldCat by OCLC and provide examples of how it can be used.
• Identify the options for searching WorldCat.
• Define cataloging standards.
• Define AACR2 and RDA.
• Identify the basic functions and tools of bibliographic control.
• Describe how bibliographic records are using in cataloging.
• Define types of cataloging.
• Define cataloging and the types of cataloging records.

A catalog helps library users locate resources to meet their information needs.

The catalog provides basic information about the item along with information about how the items can be located. In the case of physical materials, a call number is used locate the item in the library. In the case of remote materials, a hyperlink is usually provided.

A catalog is a database of the materials in a particular collection such as books and periodicals. Items are generally accessed by author, title, or subject. Most libraries have their catalog available electronically.

An Online Public Access Catalog is called an OPAC.

Online Public Access Catalog

An Online Public Access Catalog (OPAC) is an online database of resources held in a library or group of libraries.

Also known as the library catalog, users can search the databases to locate books, DVDs, and other materials available at the library. Features of many online catalogs include:


Searching an OPAC

A basic search involves entering a search keyword(s) or phrase(s). In some cases, users can search using Boolean logic using AND, OR, and NOT to locate titles. In some cases, users can use truncation such as arch#eology

An advanced search allows searching by facility. User may also limit the search by date, format, or other feature.

Results screens provide the bibliographic record, sometimes the MARC record, information about holdings and availability, and links to related authors and subjects. In some cases, options are provided for sorting results.

In the case of electronic resources, a direct link to the online journal article, e-book, audiobook, or other resource is listed. Some systems allow users to make email requests, reserve items, or download digital resources.


The Real World of OPACs

wheelAn OPAC provides an excellent way for library users to access the library’s collection both within and outside the physical library. Unfortunately, not everyone is comfortable using an OPAC.

Lack of basic computer skills can limit usability by some patrons. In some cases, the OPAC user interface may not be user friendly leading to patron frustrations.

Because the OPAC is one of the most frequently used tools for library access, it’s essential that library users be provided with accessible computer stations within the library and a quality web interface for off-site use.

Increasingly, library users are accessing the OPAC through mobile devices.

Try It!
Spend some time exploring IUCAT, IU’s OPAC.

Union Catalogs

A union catalog is a combined catalog that describes a number of library collections. For instance, each library in a school district or public library system would have it’s own catalog, but the system as a whole would maintain a union catalog.

Union catalogs assist librarians in locating and requesting materials through interlibrary loan services.

School librarians often collect multiple copies of a book for literature circle activities.

Academic libraries use union catalogs to locate uncommon works that would otherwise not be available.

Examples of Union Catalogs

Regional library consortia often work together to provide patrons with access to union catalogs.

The Utah Academic Library Consortium (UALC) provides a way to search academic library catalogs in Utah. Other states and regions have similar organizations.

The NEOS Library Consortium includes academic, government, and hospital libraries in Alberta, Canada.

Evergreen Indiana contains the catalogs of 95 Indian public, school, and institutional libraries that use Evergreen open source software for their OPACs. Try this union catalog!

When searching IUCAT, you’ll notice that you can search IUPUI’s library or any of the other libraries in the IU system. Try this union catalog!


worldcatWorldCat is a product of Online Computer Library Center, Inc. (OCLC) and is the best known example of a union catalog. It’s also the world’s largest OPAC.

OCLC is a nonprofit, membership computer library service. In addition to the OPAC, OCLC is also known for their research. Bibliographic, abstract, and full-text information is available to anyone. WorldCat Local can be added to a a library’s OPAC to help library users find items in other libraries. OCLC is known for it’s advocacy campaign Geek the Library and other campaigns to share library and information research and knowledge. OCLC also offers access to a core collection of reference databases through FirstSearch.

WorldCat searches thousands of catalogs from around the world.

WorldCat is the best known union catalog, but others include AMICUS is from Canada, Libraries Australia, and copac from the UK and Ireland.

Searching WorldCat

WorldCat allows user to search both physical items like books and music CDs, as well as digital content such as downloadable audiobooks. Article citations with links to full text are also available as well as digital versions of rare items.

Users can do a basic search, format search, or advanced search.

The advanced search includes searching by keyword, title, or author. A search can be narrowed by year, audience, content, format, and language.


Open WorldCat is a program that makes records of library collections available online. Give it a try!

Cataloging Standards

Cataloging standards ensure consistency in library catalogs. Cataloging rules allow consistency in cataloging across catalogers and libraries.

The International Standard Bibliographic Description (ISBD) is a set of rules used to describe library materials. AACR2 and MARC are two examples.

The Anglo-American Cataloguing Rules, 2nd edition (AACR2) are applied in creating bibliographic records. They detail how to describe an item. Librarians use AACR2 to create bibliographic descriptions of items in machine-readable code (MARC) records.

Recently, AACR2 has been succeeded by Resource Description and Access (RDA) released in 2010. The new code is more flexible and suitable for digital environments. It is sponsored by ALA, CLA, CILIP, as well as other global organizations.

To learn more about this shift, go to the Joint Steering Committee for Development of RDA.

Try It!
Browse the RDA Toolkit website to learn about this cataloging standard.

Bibliographic Control

Bibliographic control is the process of describing information resources (e.g., book, DVD, image, digital document) so users are able to find and locate them.

The functions of bibliographic control include a number of activities including:

Bibliographic Record

A bibliographic record is created for each item in a library collection.

The record is composed for fields that contain elements of information that include:

Types of Cataloging

catCatalogers are concerned with two types of cataloging: descriptive cataloging and subject cataloging.

Descriptive cataloging involves the physical description of the item and choice of entries. It describes what an object “is”.

It’s a hardcover book that’s 9x6 inches and has 242 pages.
This information becomes 242 p. : ill. ; 22cm.

Subject cataloging involves classification and subject indexing of the item. Items are assigned a classification number and subject headings. It describes the “aboutness” of the object.

It’s about pets including dogs, cats, fish, and frogs.
This information becomes Pets -- Juvenile literature.
The DDC is 636.

Types of Cataloging Records

recordsThere are two types of cataloging records:

Bibliographic records contain information about an item such as book, video recording, or other item.

streaming found file (1 hr., 58 min., 55 sec.) : digital, steeo., MP3 file.
electronic book reader ; 7.5 x 4.8 inc + 1 black leather case + 1 power cord

Authority records contain standardized forms for names, titles, and subjects used on bibliographic records. They also provide cross references in catalogs.

Hurricanes. See Cyclones.
Dr. Seuss. See also Geisel, Theodore.


The Online Public Access Catalog (OPAC) provides library users with a way to access the library’s collection. Union catalogs contain the collections of a number of libraries. WorldCat is the largest and best known union catalog.

Bibliographic control is the process of describing information resources. A bibliographic record is created for each item in the collection.

Descriptive cataloging involves describing the item itself, while subject cataloging focuses on content of an object.

In addition to bibliographic records, authority records are also created that focus on standarized forms of names, titles, and subjects.

| eduscapes | IUPUI Online Courses | Contact Us | 2014 Annette Lamb (Adapted from earlier s401 materials)

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