What is a DOI?
A digital object identifier, or DOI, refers to a handle that recognizes a unique object in the digital world. This label is assigned by the International Organization for Standardization (ISO) to a variety of academic, and non-academic, sources.
Why is it important to use DOIs?
The DOI system came to transform the way we use digital material. According to doi.org, DOIs implement technical and social infrastructure for the registration and use of identifiers in digital networks. It’s important to use DOIs when available as it adds credibility to the source. If a citation includes a DOI, it means the source is unique and real.
Format of a DOI
There are three different ways of writing a DOI:
- doi: xxxx or DOI: xxxx
The most recent and preferred format is the last one (https://doi.org/xxxx), but any type is valid as long as it includes the right alphanumeric identifier.
When to use a DOI instead of a URL
- If the source has a DOI, use it! Do not use the URL of the source if a DOI is available. URLs might change over time, while DOIs do not.
- If the digital source has a URL and no DOI, include the URL as reference.
- According to APA if a source doesn’t have a DOI, and it was retrieved from an academic database, do not include the URL or database information as these works are widely available.
- If the DOI is too long, APA allows the use of DOI shorteners like shortDOI® , a service created by the International DOI Foundation to create shortDOIs.
To be able to find DOIs, take a look at our guide How to find a DOI.
Frequently Asked Questions about DOIs
Is a DOI the same as a URL?
No. URLs and DOIs are not interchangeable. A DOI is a unique alphanumeric identifier that labels digital material and pinpoints its location on the internet, whereas a URL is digital locator.
What is the right way of writing a DOI?
The preferred format of a DOI is https://doi.org/xxxx, without a period at the end.
Who assigns DOIs to material?
The International Organization for Standardization (ISO) is the responsible of assigning DOIs to a variety of academic, and non-academic, sources.
Why should I use DOIs in my citations?
DOIs were invented for a reason. These alphanumeric identifiers allow readers to locate specific material in the digital world. They also add credibility to your sources.
When should I use a DOI instead of a URL?
Whenever the source has a DOI, use it! Do not use the URL of the source if a DOI is available. However, if the material does not feature a DOI, add the URL to your citation.