ISSN: The Global Standard for Periodical Identification
In the vast world of publishing, distinguishing between thousands of magazines, journals, and newspapers can be a challenge—especially when different publications share the same title. This is where the International Standard Serial Number (ISSN) becomes essential. An ISSN is a unique eight-digit code used to identify periodical publications, ensuring that librarians, researchers, and distributors can accurately order, catalog, and locate serial literature.
First drafted as an International Organization for Standardization (ISO) standard in 1971 and officially published as ISO 3297 in 1975, the system is now maintained by ISO subcommittee TC 46/SC 9. Today, it serves as the backbone for serial identification worldwide.
Key Facts
- Purpose: Uniquely identifies periodical publications (serials).
- Format: An 8-digit code divided by a hyphen (NNNN-NNNC).
- Governance: Coordinated by the ISSN International Centre in Paris.
- Scale: Over 2,500,000 numbers have been issued.
- Scope: Separate codes are assigned for different media types (e.g., print vs. electronic).
The Structure and Logic of an ISSN
An ISSN consists of eight digits, split into two four-digit groups. The first seven digits are the unique identifier, while the eighth digit is a check digit used to verify the accuracy of the number. This check digit can be a number from 0 to 9 or the letter "X" (representing the number 10).
To calculate the check digit, each of the first seven digits is multiplied by a weight based on its position (from 8 down to 2). These products are summed, and the remainder of the sum modulo 11 is calculated. If the remainder is 0, the check digit is 0; otherwise, the remainder is subtracted from 11 to find the final digit.
For example, the journal Hearing Research uses the ISSN 0378-5955, where the final 5 serves as the check digit.
Media-Specific Identifiers: p-ISSN, e-ISSN, and ISSN-L
Because the ISSN system is media-oriented, a publication that exists in multiple formats requires a different code for each. This prevents confusion in logistics and cataloging:
- p-ISSN (Print ISSN): The identifier for the paper version of a serial.
- e-ISSN (Electronic ISSN): The identifier for the online or digital version.
To bridge the gap between these versions, ISO 3297:2007 introduced the Linking ISSN (ISSN-L). The ISSN-L is a single identifier that links all media versions of the same content. It is typically based on the ISSN of the first published medium. This allows search engines, library catalogs, and services like OpenURL to group all versions of a journal together regardless of format.
Encoding ISSNs in Barcodes and URNs
For commercial and digital distribution, ISSNs are often integrated into other systems. In retail, they can be encoded into EAN-13 barcodes. This is done by using the "country code" 977, followed by the first seven digits of the ISSN, two publisher-defined digits, and a final EAN check digit.
In the digital realm, an ISSN can be formatted as a Uniform Resource Name (URN) by adding the prefix urn:ISSN:. For instance, a publication might be referred to as urn:ISSN:0953-4563. Note that URN namespaces are case-sensitive and use all caps for the ISSN prefix and the check digit "X".
Administration and the ISSN Register
The assignment of these codes is managed by a global network of National Centres, usually hosted within national libraries. These centres are coordinated by the ISSN International Centre (CIEPS) in Paris, an intergovernmental organization established in 1974 via an agreement between UNESCO and the French government.
The International Centre maintains the ISDS Register (International Serials Data System), a comprehensive database of all assigned ISSNs. As of the end of 2016, this register contained records for 1,943,572 items. While the full register is available via subscription, users can often find ISSN information on publication websites or through services like WorldCat.
ISSN vs. Other Identifiers
It is common to confuse the ISSN with the ISBN, but they serve different purposes. While an ISBN identifies a specific book, an ISSN identifies the entire serial title. An ISSN is an anonymous identifier; it contains no embedded information about the publisher or location. Consequently, if a serial undergoes a major title change, a new ISSN must be assigned.
For more granular identification, other systems are built upon the ISSN, such as the Publisher Item Identifier (PII) and the Serial Item and Contribution Identifier (SICI), which allow for the identification of specific articles or volumes.
| Feature | ISSN | ISBN | DOI |
|---|---|---|---|
| Full Name | International Standard Serial Number | International Standard Book Number | Digital Object Identifier |
| Primary Target | Periodicals (Magazines, Journals) | Individual Books | Digital Objects (Articles, Reports) |
| Scope | Entire Serial Title | Specific Edition/Book | Specific Content Item |
| Media Logic | Media-oriented (p-ISSN/e-ISSN) | Format-specific | Content-oriented |
Frequently Asked Questions
What is the difference between p-ISSN and e-ISSN?
A p-ISSN is assigned to the print (paper) version of a periodical, while an e-ISSN is assigned to the electronic (online) version. If a journal is published in both formats, it will have both codes.
What is an ISSN-L?
The Linking ISSN (ISSN-L) is a unique identifier used to group all media versions of a serial (such as print and electronic) under one umbrella, facilitating easier searching and retrieval.
How is the ISSN check digit calculated?
The check digit is calculated using a weighted sum of the first seven digits (multiplied by 8 through 2). The sum is processed modulo 11; if the result is 10, the check digit is represented by the letter "X".
Does an ISSN identify a specific article?
No, an ISSN identifies the entire periodical title. To identify a specific article within a journal, other identifiers like the Digital Object Identifier (DOI) or the Serial Item and Contribution Identifier (SICI) are used.
What happens if a magazine changes its name?
Because the ISSN is associated with the title of the serial, a major title change requires the assignment of a new ISSN.