Skip to Main Content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.

Persistent Identifiers

NTL Guide to DOIs & ORCID iDs for DOT Researchers

What Is a Digital Object Identifier (DOI)?

Digital Object Identifiers (DOI) are the most widely known and used PIDs.               

DOIs are persistent unique identifiers designed for research objects, such as articles, books and book chapters, conference proceedings, data sets, etc. [1] The DOI system is designed to identify objects wherever they are located on the web, unlike a URL which points to a specific location on the web which may change or disappear over time. DOIs alleviate the problem of dead links or link rot. [2]

DOIs are typically issued at the time of an object's publication, much like an ISBN or serial number. All DOIs begin with a 10 and contain a prefix and a suffix separated by a slash. The prefix is a unique number of four or more digits assigned to organizations; the suffix is assigned by the publisher and identifies the object.

Who manages DOIs?

  • To date approximately 190 million DOIs have been assigned through a world-wide federation of Registration Agencies (RA). RAs are members of the International DOI Foundation, and each RA offers systems to customers who wish to assign DOIs. The DOI System standard was created by the International DOI Foundation and adopted as International Standard ISO 26324 in 2012.  

‚ÄčWhat should have a DOI?

  • A DOI can be assigned to any object (physical, digital or abstract) that you wish to identify with a permanent, globally unique identifier. DOIs are primarily to information objects that are to be shared with an interested user community and/or managed as intellectual property. 

Where can you find DOIs in documents?

The examples below show the general location of DOIs in digital repository holdings, in this instance Elsevier's ScienceDirect and NTL's ROSAP repositories. 

  • Abstract or Summary Page: On the landing page for an article the full link for its DOI is often found near the top, under the title, or within the source information. 




  • Downloaded PDF: On a downloaded PDF for a publication the DOI can typically be found on the cover page (if the publication has one) or near the top or bottom of the first page.

Can’t find a DOI?

Although DOIs are becoming increasingly popular and often required, not all publications have DOIs or list DOIs within databases.

  • If you are unable to find a DOI, a good way to verify whether or not the publication has a DOI is to use a free search service provided by one of the DOI RAs such as: 
    • CrossRef: searches the metadata of publications and has the option to search by title, author, DOI, ORCID, etc.
    • DataCite: has divided search sections (Works, People, Data Centers, Members) that allow for a refined search based on what the user is looking for. 

Why DOIs Are Important for Your Research

Why use a DOI?

DOIs are persistent, meaning they have been designed with the ability to provide lasting information on where objects or information about them can be found on the internet. [3] Although Information about an object may change over time, such as where it can be found on the web, its DOI will never change.


  • Aid in citation tracking, ensuring a researcher has accurate metrics on how and where their research outputs are being used or referenced. 
  • Increase data sharing and reuse, by making information discoverable over the long-term. 
  • Are required or strongly encouraged in certain citation style guidelines.
  • Are becoming a required part of repository, journal, and database submission workflows. 

Citation Tracking

The DOI has become an important piece of publication metadata that guarantees continued access to, at minimum, the metadata for an object, and helps researchers track the use of their articles. The ability to track an article's metrics helps researchers measure the impact of their work and the number of times it is cited, discussed, shared, bookmarked, or otherwise used across the Internet.

It is important to note that NTL’s publications are grey literature and not scholarly publications, since it is publicly available gov. data and is often used without proper citations. As a result, the use of metric tools won’t always provide a full picture of where or how the data is being used. We are currently in the process of preparing to share our own metrics within the repository, but this project has not been fully realized yet.  

The below tools are not endorsed by NTL, but offer some options for researchers who want to explore the potential reach of their publications. Additionally, each has its own limits on the information it is able to produced, which are mentioned below.

Ways to track your DOIs?

Beyond ensuring continued access to research, DOIs offer the benefit of being traceable across the web, which allows metrics of an article's success to be tracked over time. In the digital world this can extend beyond traditional metrics, such as article citation count. Alternative metrics or altmetrics aim at capturing success through additional means, including article mentions on Twitter, the number of times an article is publicly bookmarked or saved to a citation manager, etc. [4] The best way to ensure that altmetrics can be collected for an object is to place it in a repository that already has tools in place to track altmetric data, but there are other services that can help gather altmetrics. 

  • Altmetric it! allows anyone to easily get altmetric results for a published object by adding the free Altmetric it! bookmarklet to a browser's bookmarks toolbar. After adding the bookmarklet an individual will simply need to click the link while viewing an object to get its altmetrics. However, the bookmarklet only works on PubMed, arXiv or pages containing a DOI with Google Scholar friendly citation metadata and Twitter mentions are only available for articles published since July 2011.

  • Paperbuzz: Paperbuzz is “a free and open way to track the online buzz around scholarly articles.” A user searches using a DOI and then Paperbuzz generates a report for references found on the internet. The main issue with Paperbuzz is that its data isn’t complete for objects published before 2017, thus greatly limiting its effectiveness but you can get alerts for future article mentions when they occur.

  • PlumX: “PlumX Metrics provide insights into the ways people interact with individual pieces of research output (articles, conference proceedings, book chapters, and many more) in the online environment.” PlumX is broken down into five categories: citations, usage, captures, mentions, and social media. PlumX is designed for journals, repositories, data providers, and platform partners, not individual users. However, organizations that make use of PlumX allow users to easily see the altmetrics for an object on the side bar when viewing it on their site.

  • Google Scholar Citation Profile: Making a profile is a simple way to track both a single object's metrics, and a researcher’s complete bibliography. Google Scholar Citations tracks total citations, as well as a researcher's h-index and i10-index, which can be further broken down by year.