What is a co-author? Meaning, duties and rights
What makes someone a co-author, what the large publishers require of co-authors, and who belongs in the acknowledgements instead — from ICMJE, COPE and publisher policies.
Sources read 16 October 2026
A co-author is any author of a paper other than, or alongside, the corresponding author. Under ICMJE’s recommendations every author — co-authors included — must meet all four authorship criteria, including approving the final version and agreeing to be accountable for the work. People who helped but do not meet all four are acknowledged, not listed as authors.
The four criteria every author must meet
ICMJE (Recommendations, PDF updated January 2026) requires all four:
- A substantial contribution to the conception or design of the work, or to acquiring, analysing or interpreting data.
- Drafting the work or revising it critically for important intellectual content.
- Final approval of the version to be published.
- Agreement to be accountable for all aspects of the work.
COPE’s authorship guidance sets the same two minimums in plainer terms: a substantial contribution, and accountability for the work. Contributor roles can be recorded with CRediT, a 14-role taxonomy that became the ANSI/NISO standard Z39.104-2022 on 14 January 2022 — CRediT explained.
Who is not a co-author
- Someone whose only role was obtaining funding, general supervision of a research group, or writing and editing help — ICMJE lists these as not sufficient on their own.
- An AI tool. ICMJE says chatbots cannot be authors because they cannot take responsibility for the work.
- A senior colleague added as a favour or to lend weight — COPE calls this gift or guest authorship (ghost, gift and guest authorship).
These contributions belong in the acknowledgements — see our acknowledgements guide and examples.
What the large publishers require of co-authors
| Publisher | Confirming co-authors | Changing the author list after submission | After acceptance |
|---|---|---|---|
| Elsevier | The corresponding author confirms all co-authors approved the final version; some journals also email each co-author to confirm (optional, per journal). | Only in exceptional cases, at the editor’s discretion, with all authors agreeing. | Not allowed. |
| Springer / Nature Portfolio | One corresponding author acts for all; every author must approve any change to the list, its order or the corresponding author. | Generally not at revision (Springer); exceptions at the Editor-in-Chief’s discretion. | Not allowed. |
| PLOS | Every author receives an email to confirm the submission. | Through an Authorship Change Form agreed by all authors. | Generally not considered between acceptance and publication. |
| Wiley | The corresponding author makes sure all co-authors approve the manuscript. | Through Wiley’s author list change form, agreed by the whole author group. | Not stated on the ethics page. |
From each publisher’s authorship or ethics policy, read 16 October 2026. Journals do not settle authorship disputes themselves (Springer, Wiley); COPE publishes flowcharts for editors on adding or removing an author.
Co-author, corresponding author, first author
The corresponding author handles communication with the journal through submission, review and publication and stays available afterwards (ICMJE). It need not be the first or the senior author (Springer Nature). More than one corresponding author can appear on the published paper at Springer Nature and PLOS, but their submission systems accept only one; Wiley asks for one “Responsible Corresponding Author” at submission. At most publishers the corresponding author’s country also decides an APC waiver — who counts for a waiver.
The first author position carries field-specific meaning — first vs last author and author order conventions.
Equal contribution (co-first authors)
Springer and Nature Portfolio journals may mark one group of authors as having contributed equally and one group as having jointly supervised the work; other equal contributions go in the author contributions statement. Nature marks equal co-authors with a symbol and the line that they contributed equally; with more than three, it moves the statement into the author contributions.
ORCID for co-authors
Nature Portfolio and PLOS require an ORCID iD from the corresponding author and encourage it for co-authors; PLOS publishes a co-author’s ORCID only if it is linked before acceptance. Springer “strongly recommends” ORCID. We did not find a requirement for every co-author at Elsevier, Springer Nature or Wiley.
Questions
What does co-author mean?
A co-author is any listed author of a paper alongside the corresponding author. Under ICMJE, each must have made a substantial contribution, helped draft or revise the paper, approved the final version and agreed to be accountable for it.
Can a co-author be removed after acceptance?
At Elsevier and at Springer and Nature Portfolio journals, no — authorship cannot be changed after acceptance. PLOS generally does not consider changes between acceptance and publication.
What is the difference between a co-author and a contributor?
A co-author meets all four ICMJE criteria and is listed in the byline. A contributor who does not meet all four is named in the acknowledgements, with what they did.
Sources for this page
- ICMJE
- Defining the Role of Authors and Contributors; Recommendations PDF (updated January 2026)
- COPE
- Authorship discussion document, How to recognise potential authorship problems
- CRediT
- ANSI/NISO Z39.104-2022
- Elsevier
- Publishing ethics; Co-author verification
- Springer Nature
- Springer journal policies; Nature Portfolio authorship; Corresponding author defined
- PLOS
- PLOS ONE authorship
- Wiley
- Wiley ethics guidelines