Digital Object Identifier (DOI)

1. Introduction: The DOI system provides a technical and social infrastructure for the registration and use of persistent interoperable identifiers, called DOIs, for use on digital networks. The DOI system originated in a joint initiative of three trade associations in the publishing industry (International Publishers Association; International Association of Scientific, Technical and Medical Publishers; Association of American Publishers). Although originating in text publishing, the DOI was conceived as a generic framework for managing identification of content over digital networks, recognising the trend towards digital convergence and multimedia availability. The system was announced at the Frankfurt Book Fair 1997. The International DOI® Foundation (IDF) was created to develop and manage the DOI system, also in 1997.

From its inception the IDF worked with the Corporation for National Research Initiatives (CNRI) as a technical partner, using the Handle System developed by CNRI as the digital network component of the DOI system. CNRI remains a technical partner of the IDF.

2. Definition: A Digital Object Identifier (DOI) is a unique alphanumeric string assigned by a registration agency (the International DOI Foundation) to identify content and provide a persistent link to its location on the Internet. The International DOI Foundation (IDF) is a not-for-profit membership organization providing Digital Object Identifier (DOI) services and registration, and is the registration authority for the ISO standard (ISO 26324) for the DOI system.

3. Registration with IDF: Registration Agency membership is only available to organizations which (a) have participated in the IDF as a General Member; (b) have made a successful application to the IDF Board to be appointed as a Registration Agency; (c) have signed a Registration Agency Agreement with the IDF. Registration Agencies will typically register many thousands or millions of DOI names, and have multiple customers and services, thereby generating economies of scale.

            Anyone interested to have DOI for them, must use a service offered by a DOI Registration Agency (RA). RAs collect metadata, assign DOI names, and offer other services such as reference linking or metadata lookup. Anyone does not need to be a member of the International DOI Foundation in order to work with an RA.

            The cost of registering new DOI names depends on the services you purchase. Each RA is different, and each is free to offer their own business model. The IDF does not determine the costs charged to end users.

Membership fees fall due annually on the anniversary of joining. The current annual fees for membership to the IDF includes Charter Members ($US 70,000); General Members ($US 35,000), Registration Agency Members (the fee varies) and Affiliate Members ($2,000). The fee for General Members may be reduced at the sole discretion of the Board, subject to a minimum fee of $US 11,500 per annum. There are no differences in member rights and benefits between Charter and General, nor for those for which a reduced fee is payable.

4. Components of DOI: All DOI numbers begin with a 10 and contain a prefix and a suffix separated by a slash. “10” is the directory indicator which distinguishes the entire set of character strings (prefix and suffix) as digital object identifiers within the resolution system. The prefix is a unique number of four or more digits assigned to organizations; the suffix is assigned by the publisher and was designed to be flexible with publisher identification standards. There is no limitation on the length of a DOI name. The prefix is assigned to an organization that wishes to register DOI names. The DOI name is case-insensitive and can incorporate any printable characters from the legal graphic characters of Unicode. The publisher assigns a DOI when your article is published and made available electronically.

5. Location of DOI: The DOI is typically located on the first page of the electronic journal article, near the copyright notice. The DOI can also be found on the database landing page for the article.

6. DOI® Handbook: The DOI® Handbook is the primary source of information about the DOI® system. The DOI name 10.1000/182 identifies the currently applicable latest version of the handbook. This version was written to reflect the approval and publication of ISO 26324: DOI System, in 2012, and includes relevant ISO terminology.

7. DOI as ISO Standard: In 2000 the syntax of the DOI was standardised through NISO (ANSI/NISO Z39.84-2000) (reconfirmed 2005, 2010). The DOI system was approved as an ISO standard (ISO 26324) in 2010.

8. Usefulness of DOI: Applications of the DOI system include but are not limited to managing information and documentation location and access; managing metadata; facilitating electronic transactions; persistent unique identification of any form of any data; and commercial and non-commercial transactions. The DOI is useful in the following ways-

a) Persistent Link: If the URLs or services change over time, e.g., the resource moves, rearranged the same DOI will continue to resolve to the correct resources or services at their new locations.

b) Interoperability: Interoperability with other data from other sources.

c) Extensibility: Extensibility by adding new features and services through management of groups of DOI names.

d) Platform Independence: Single management of data for multiple outputs formats (platform independence).

e) Dynamic Updating: Dynamic updating of metadata, applications and services.

f) Citation Linking: The first application of the DOI system, citation linking of electronic articles by the Crossref Registration Agency, was launched in 2000.

9. Conclusion: The DOI name itself remains persistent through ownership changes and unaltered once assigned. The DOI name is an “opaque string” or “dumb number” — nothing at all can or should be inferred from the number in respect of its use in the DOI system. The only secure way of knowing anything about the entity that a particular DOI name identifies is by looking at the metadata that the Registrant of the DOI name declares at the time of registration. This means, for example, that even when the ownership of a particular item changes, its identifier remains the same — in perpetuity. This is why the DOI name is called a “persistent identifier”.