# Joint first authors

**URL:** <https://community.crossref.org/t/joint-first-authors/16271>\
**Category:** Technical Support\
**Tags:** rest-api, schema, content-registration, xml\_support, credit\
**Created:** [17 August 2026 11:08 UTC](https://community.crossref.org/t/joint-first-authors/16271 "2026-08-17T11:08:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rhiannon-ppl](https://sea2.discourse-cdn.com/flex020/user_avatar/community.crossref.org/rhiannon-ppl/32/393_2.png) [@rhiannon-ppl](https://community.crossref.org/u/rhiannon-ppl)\
**Post date:** [17 August 2026 11:08 UTC](https://community.crossref.org/t/joint-first-authors/16271/1 "2026-08-17T11:08:58Z")

</div>

Is it possible to register metadata where two or more contributors both have @sequence=“first”, using an XML upload deposit? I have tried updating an existing record with two authors, using replacement XML where both contributors have @sequence=“first”, but the metadata have not changed: there is still a “first” and an “additional” contributor. Is this working as intended, or am I doing something wrong?

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**Author:** ![boutaleb](https://sea2.discourse-cdn.com/flex020/user_avatar/community.crossref.org/boutaleb/32/2252_2.png) [@boutaleb](https://community.crossref.org/u/boutaleb)\
**Post date:** [17 August 2026 14:27 UTC](https://community.crossref.org/t/joint-first-authors/16271/2 "2026-08-17T14:27:07Z")

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In my view, it may be useful here to distinguish clearly between **author order, equal contribution, and corresponding authorship** , as these represent different types of information.

In Crossref metadata, `sequence="first"` and `sequence="additional"` primarily describe the **sequence of contributors**. Crossref also notes that there is no more detailed numbering of author positions, and that many systems reusing these metadata rely on the order in which contributors are deposited when displaying the author list.

Therefore, an author recorded as `additional` should not, in my view, be interpreted as having made a lesser scientific contribution.

Let us take a simple example:

_Nadia Boutaleb¹†, Meriem Mahmoudi²†, …_\*

- _Corresponding author_  
† _These authors contributed equally to this work and share first authorship._

In this example, Nadia Boutaleb and Meriem Mahmoudi are explicitly recognised in the published article as having contributed equally and sharing first authorship. However, the metadata still need to represent the contributors in a particular sequence. One author may therefore appear as `sequence="first"` and the other as `sequence="additional"` for sequencing purposes, without this necessarily implying any difference in the scientific value of their respective contributions.

The recent introduction of **Crossref Schema 5.5** seems particularly relevant in this context. It now allows **multiple roles to be assigned to an individual contributor** , explicitly supports the **`corresponding-author`** role and, importantly, incorporates the **CRediT taxonomy and its 14 contributor roles**.

This means that the metadata can now describe much more precisely who contributed to conceptualisation, methodology, investigation, data curation, writing, supervision, and so on, independently of where a person’s name appears in the author list.

I would therefore distinguish between:

**Author order** → `sequence`  
**Nature of contribution** → CRediT roles  
**Corresponding author** → `corresponding-author`  
**Equal contribution / joint first authorship** → a conceptually distinct piece of information

CRediT therefore provides a much richer description of what each contributor actually did, but **joint first authorship is not, to my knowledge, one of the 14 CRediT roles**.

This seems to leave an interesting question: while Schema 5.5 allows author order, corresponding authorship, and individual contributions to be represented separately and with greater granularity, **how should equal first authorship itself be explicitly represented?**

Unless I am overlooking something in the new schema, I would not necessarily expect assigning `sequence="first"` to two contributors to be the mechanism for expressing equal contribution.

So, with the introduction of Schema 5.5, I would be particularly interested to know: **what is Crossref’s recommended way of explicitly representing joint first authorship in the metadata?**

I would be very interested to hear Crossref’s :crossref_icon: clarification on this point.

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**Author:** ![ifarley](https://sea2.discourse-cdn.com/flex020/user_avatar/community.crossref.org/ifarley/32/44_2.png) [@ifarley](https://community.crossref.org/u/ifarley)\
**Post date:** [17 August 2026 20:12 UTC](https://community.crossref.org/t/joint-first-authors/16271/3 "2026-08-17T20:12:47Z")

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Hello @rhiannon-ppl ,

Thanks for your message. There is no limit in the schema on the number of ‘first’ or ‘additional’ authors. While this is an editorial decision, members can signal equal first authorship @boutaleb by including multiple authors as ‘first,’ like in this example: 10.14336/AD.2017.1213

> **[Epigenetic Regulation of Bone Marrow Stem Cell Aging: Revealing Epigenetic...](https://doi.crossref.org/search/doi?pid=support@crossref.org&format=unixsd&doi=10.14336%2FAD.2017.1213)**

```auto
<contributors>

<person_name sequence="first" contributor_role="author">

<given_name>Dimitrios</given_name>

<surname>Cakouros</surname>

</person_name>

<person_name sequence="first" contributor_role="author">

<given_name>Stan</given_name>

<surname>Gronthos</surname>

</person_name>

</contributors>

```

@rhiannon-ppl I see that in a private message you mentioned that you recently updated the record associated with DOI 10.56367/OAG-051-12579 to include two ‘first’ authors:

```auto
<contributors>

<person_name sequence="first" contributor_role="author">

<given_name>Scott D</given_name>

<surname>Pegan</surname>

<affiliation>University of California Riverside</affiliation>

</person_name>

<person_name sequence="first" contributor_role="author">

<given_name>Mohammad M</given_name>

<surname>Sajadi</surname>

<affiliation>University of Maryland School of Medicine</affiliation>

</person_name>

</contributors>

```

There are indexing lags in our system. After a successful submission - be it a new registration or update - it can take up to 24 hours for those updates to be reflected in our APIs and in [search.crossref.org](http://search.crossref.org) (which is powered by [api.crossref.org](http://api.crossref.org)). I think that was the issue here. I see that the metadata record for this DOI has been updated in our REST API: [https://api.crossref.org/works/10.56367/OAG-051-12579](https://api.crossref.org/works/10.56367/OAG-051-12579)

 ![Screenshot 2026-08-17 at 3.09.29 PM](https://us1.discourse-cdn.com/flex020/uploads/crossref/original/2X/e/efc4e245c2d76110dc52f51e603609bc9386da45.png)

My colleague @pdavis wrote what we call a ‘[ticket of the month](https://community.crossref.org/tag/ticket-of-month/147)’ post about this with the various lags in our system a couple of years ago: [Ticket of the month - September 2023 - A DOI-namic timeline](https://community.crossref.org/t/ticket-of-the-month-september-2023-a-doi-namic-timeline/4143)

Warm regards,

Isaac