In our recent blog post, PIDs 101, we covered a wide range of Persistent Identifiers (PIDs) and looked at how they link together, and what the future holds for them. This week we are drilling down to investigate Digital Object Identifiers (DOIs) in more detail.

In the last post we discussed DOIs being a unique registration number for a Digital Object, and the fact that a digital object in this context could be an article or a dataset, but it could equally be any of a number of other item types, such as on this list defined by Crossref.

How do DOIs work?

Each publisher, funder or repository that is registered to provide DOIs is given a unique registration number. This number, along with the ‘10.’ common to all DOIs, forms the first part of a DOI, called the prefix – shown below. Each registered provider is then responsible for choosing their own suffix pattern.

This is where DOIs get extra clever. Each registered provider can construct the suffixes to their own design, and these can be as simple or as complex as needed. For example, the Wellcome trust uses DOIs for identifying grants as well as publications, and PLOS uses different suffixes to identify which articles come from which journal – for example:

In the three PLOS DOI examples above, the unique registration number is 1371. Each suffix starts by designating the item type: journal, and then follows with an acronym of the individual journals themselves, pbio (PLOS Biology), pone (PLOS one) and pgen (PLOS Genetics). Each journal then uses article numbers in a predetermined sequence for the final part of the DOI. These numbers match the article numbers shown in the article citations. Every registered provider needs a scheme like this that they use to generate their DOIs, as it is essential that each item receives a unique DOI.

For every DOI that is generated, it is the responsibility of the provider to send metadata and a link to the top level webpage for the item to their individual registration agency. In the UK this is most likely to be Crossref or Datacite. This metadata is then made openly available so it can be used to build overarching databases or added into other tools and services like the search interface at doi.org. Crossref and DataCite make the metadata and DOIs registered with them openly available via APIs so that it can be used in databases like Europe PubMed Central.

The different publishers, repositories, universities and funders all have a responsibility to keep the metadata of all of the DOIs they generate up to date. This is important in order for the DOI to be persistent. For example, if your chosen journal changes publisher after your article has been published, it is the responsibility of the publisher to facilitate updating the metadata of every article so that you will still be able to find your article using the DOI.

Why is having a DOI beneficial?

The purpose of a DOI is to accurately identify, link to and discriminate between online works. DOIs are unique to the work they identify and permanently link to it. This means that a DOI must link to the authoritative and authentic web presence for the work hosted on a sustainable platform.

So, having a DOI for your work (whatever it may be) means that it will always be findable: even if the journal where it was originally published no longer exists, there will always be a record of your work no matter how much time has passed. It also helps ensure that your work is cited properly, and that every mention of it is correctly attributed and easy to track. If your work has a DOI, it can be included in other tools like Altmetric or Plum Analytics. These tools track mentions of works in social media, news media, policy documents and other places.

How do I get a DOI for my work?

It is relatively unusual for journals to be unable to provide you with a DOI for your article. If your publisher does not have the facility to give you a DOI, or you wish to get a DOI for another type of material, the simplest way to go about getting one is to create a record in a repository that can provide a DOI for you.

At UCL we have the Research Data Repository (RDR) which can accept a wide range of outputs including data, figures, presentations, software, posters, even images and other media. There is the option in the record creation process to ‘Reserve’ a DOI which will become live once the record is checked and verified by the RDR team.

Outside UCL, there are also independent repositories that are able to give you a DOI. You can choose a subject repository appropriate for your data – there is lots of information available on the Research Data Management team website – or a generic one such as the UK Data Archive, Zenodo, Figshare or Dryad.