Missing article citations!

Hello all,

We, Crossref Technical Support, get questions from authors, members, aggregators, librarians, and other service providers about missing article citations. We get it. Those connections between works, especially citations, are a big deal!

In this post, I wanted to highlight the most straightforward example of why we may not be counting a citation from a citing DOI in the cited DOI’s metadata record.

An example message from an author:

Dear Crossref,

Greetings. I am writing to inquire about a missing citation of our article. Crossref has indexed the following article “A Rare Clinical Condition That Can Mimic Bladder Malignancy: Primary Bladder Amyloidosis.” DOI: 10.5505/GJU.2024.73745. Although, the aforementioned article has clearly cited our work in the article “Primary bladder amyloidosis mimicking bladder cancer complicated by bladder rupture: A case report” https://doi.org/10.1002/ccr3.5140, our article has not received any citation neither on Crossref or Google Scholar.

I have contacted the journal editorial board as mentioned in the email attached, however they suggest that Crossref will be able to solve this issue.

So, let’s look at the DOI in question: 10.1002/ccr3.5140 - here’s the DOI’s full record in our XML API. We can see in that record that the cited-by count in our system is 1:

This means that one other DOI registered with Crossref has listed DOI 10.1002/ccr3.5140 in the reference metadata registered. That DOI is: 10.1002/ccr3.5186

And, here’s what that looks like in the XML registered with us:

Okay, what does that mean?
The problem in this example, and the reason the cited-by count of DOI 10.1002/ccr3.5140 isn’t 2, is that the citing DOI 10.5505/GJU.2024.73745 registered with Crossref by member LookUs Bilisim A.S. does not include any reference metadata. Therefore, the Crossref system is unable to make cited-by connections between DOIs 10.1002/ccr3.5140 and DOI 10.5505/GJU.2024.73745 (published in the Grand Journal of Urology).

Including reference metadata in the records registered with us is optional, so I cannot make LookUs Bilisim A.S. register this metadata, albeit including reference metadata is best practice. I recommend contacting LookUs Bilisim A.S. and/or Grand Journal of Urology and requesting that they begin registering reference metadata with us for your DOI and all DOIs registered in the Grand Journal of Urology so that we, Crossef, can make these cited-by connections for your DOI (and others).

This claim that Crossref will be able to solve this issue is inaccurate. All DOI metadata, including references, is provided to us by our publisher members. Crossref does not update, edit, or correct publisher-provided metadata directly. We simply do not know the reference metadata for this DOI or any of the other 158 million plus DOIs registered with us without our members including that metadata in the records they register.

Why don’t all of your members register reference metadata?
Good question. Registration of reference metadata is optional (and, not all content registered will have references, albeit most do). We always say that we believe, for most content, that the reference metadata is the most valuable or important optional metadata. Obviously that reference matching is near and dear to us, since it’s in our organizational name and foundational to our mission.

Beyond that, there’s no additional charge to our members for registering reference metadata. Said another way, and to be candid, metadata records registered without references are not taking full advantage of the content registration fees paid to us.

Thanks for reading,