Thursday, September 17, 2015

On having multiple DOI registration agencies for the same journal

On Friday I discovered that BHL has started issuing CrossRef DOIs for articles, starting with the journal Revue Suisse de Zoologie. The metadata for these articles comes from BioStor. After a WTF and WWIC moment, I tweeted about this, and something of a Twitter storm (and email storm) ensued:

To be clear, I'm very happy that BHL is finally assigning article-level DOIs, and that it is doing this via CrossRef. Readers of this blog may recall an earlier discussion about the relative merits of different types of DOIs, especially in the context of identifiers for articles. The bulk of the academic literature has DOIs issued by CrossRef, and these come with lots of nice services that make them a joy to use if you are a data aggregator, like me. There are other DOI registration agencies minting DOIs for articles, such as Airiti Library in Taiwan (e.g., doi:10.6165/tai.1998.43(2).150) and ISTIC (中文DOI) in China (e.g., doi:10.3969/j.issn.1000-7083.2014.05.020) (pro tip, if you want to find out the registration agency for a DOI, simply append it to, e.g. These provide stable identifiers, but not the services needed to match existing bibliographic data to the corresponding DOI (as I discovered to my cost while working with IPNI).

However, now things get a little messy. From 2015 PDFs for Revue Suisse de Zoologie are being uploaded to Zenodo, and are getting DataCite DOIs there (e.g., doi:10.5281/zenodo.30012). This means that the most recent articles for this journal will not have CrossRef DOIs. From my perspective, this is a disappointing move. It removes the journal from the CrossRef ecosystem at a time when the uptake of CrossRef DOIs for taxonomic journals is at an all time high (both ZooKeys and Zootaxa have CrossRef DOIs), and now BHL is starting to issue CrossRef DOIs for the "legacy" literature (bear in mind that "legacy" in this context can mean articles published last year).

I've rehearsed the reasons why I think CrossRef DOIs are best elsewhere, but the keys points are that articles are much easier to discover (e.g., using, and are automatically first class citizens of the academic literature. However, not everybody buys these arguments.

Maybe a way forward is to treat the two types of DOI as identifying two different things. The CrossRef DOI identifies the article, not a particular representation. The Zenodo DOI (or any DataCite DOI) for a PDF identifies that representation (i.e., the PDF), not the article.

Having CrossRef and Zenodo  DataCite DOIs coexist

This would enable CrossRef and Zenod DOIs to coexist, providing we can (a) have some way of describing the relationship between the two kinds of DOI (e.g., CrossRef DOI - hasRepresentation -> Zenodo DOI).

This would give freedom to those who want the biodiversity literature to be part of the wider CrossRef community to mint CrossRef DOIs to do so. It gives those articles the benefits that come with CrossRef DOIs (findability, being included in lists of literature cited, citation statistics, customer support when DOIs break, altmetrics, etc.)

It would also enable those who want to ensure stable access to the contents of the biodiversity literature to use archives such as Zenodo, and have the benefits of those DOIs (stability, altmetrics, free file storage and free DOIs).

Having multiple DOIs for the same thing is, I'd argue, at the very least, unhelpful. But if we tease apart the notion of what we are identifying, maybe they can coexist. Otherwise I think we are in danger of making choices that, while they seem locally optimal (e.g., free storage and minting of DOIs), may in the long run cause problems and run counter to the goal of making the taxonomic literature has findable as the wider literature.