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DOI & PMID: What Are They?

This guide will assist you with understanding DOIs and PMIDs and how they are used in scholarly work.

What is a DOI?

A DOI (Digital Object Identifier) is a unique combination of letters and numbers used to permanently identify an article or other work and provide a stable link to it online. Think of it as a permanent digital address for scholarly content.

Easier Information Retrieval

DOIs identify with the content rather than a location. If the item changes location, the publisher is responsible for pointing the DOI to the new location.

Parts of a DOI


DOI syntax has two parts: prefix and suffix. The prefix consists of two parts, the directory and registrant, and is assigned by a DOI registration agency. The suffix is assigned by the owner or publisher of the identified object. In order to use this syntax to implement resolution, the web address (https://doi.org/) must be placed before the prefix.
Source: Khedmatgozar, Hamid. (2020). Digital identifiers in scientific publishing and e-health. Medical Writing. 29. 74-78.

DOI Formats - Active or Inactive

When you locate an article, the DOIs may be formatted as active or inactive.

An active DOI looks like a hyperlink.

An inactive DOI omits the https://doi.org/ and often starts with 10 (especially if assigned before 2011).

  • DOI: 10.1037/a0040251

How Do I Make a DOI Active?

Simply add https://doi.org/ OR https://dx.doi.org/ before the DOI number to make it active.

Find Items with Inactive DOIs

Need to resolve a DOI that is in an inactive format?

  • Go to: https://dx.doi.org/
  • Type or paste a known DOI name exactly—including its prefix and suffix—into the text box at the link above and then click ‘submit’ to resolve it.

DOIs are NOT Universal

Not all articles, or other information sources, have a DOI.

You can still cite an article without a DOI by includeing the article's URL, if available, or, if accessed through a database, cite it as your would a print article, omitting the DOI and database information.