Author Contribution Statement: Examples and How to Write One

An author contribution statement is a short section in a published paper, placed near the acknowledgments and references, that names each author and specifies what that person did. It can be a free-text paragraph the authors write themselves, or a structured statement built from CRediT‘s 14-role taxonomy — separate from ICMJE’s authorship criteria for who qualifies as an author.

What an author contribution statement is — and isn’t

An author contribution statement is not the same thing as authorship criteria. Authorship criteria (ICMJE’s four-part test is the reference point most biomedical and many other journals use) decide who qualifies to be listed as an author at all. A contribution statement is a separate, additional disclosure that runs on top of that decision: once a list of authors is settled, the statement says what each of those specific people did. The ICMJE’s own recommendations describe this as an editorial option layered on top of its authorship criteria, not a competing standard: “Some journals now request and publish information about the contributions of each person named as having participated in a submitted study, at least for original research,” and editors are “strongly encouraged to develop and implement a contributorship policy,” though ICMJE does not mandate a single required format for it.

Operationally, a passage counts as an author contribution statement if it (a) names or otherwise identifies each author, (b) attaches a specific role or activity to each of them individually rather than describing the work as a whole, and (c) is published as part of the article’s front or back matter, not held internally by the journal. A generic acknowledgments line (“all authors contributed to and approved the manuscript”) does not qualify — it doesn’t differentiate individual roles, which is the entire point of the disclosure.

Why journals started asking for this

The contribution-statement model traces to a specific, citable proposal: Drummond Rennie, Veronica Yank, and Linda Emanuel’s 1997 JAMA paper “When Authorship Fails: A Proposal to Make Contributors Accountable,” which argued that the traditional single “author” credit obscured who had actually done what — and who was accountable for which part — on multi-author papers (JAMA. 1997;278(7):579–585, doi:10.1001/jama.1997.03550070071041). The same year, then-BMJ editor Richard Smith made the case in a widely cited editorial, “Authorship is dying: long live contributorship” (BMJ, 20 September 1997), for replacing binary authorship credit with an explicit list of contributions and a named guarantor. A handful of biomedical journals began requesting contributorship statements in their instructions to authors shortly afterward, and the practice was picked up into ICMJE’s recommendations as an option journals could adopt.

What ICMJE never did was specify a required vocabulary for the roles themselves — journals that wanted a statement were free to invent their own category list or simply ask for free text. That gap is what the CRediT taxonomy was later built to close: a fixed, shared set of 14 contributor roles, first published in 2014 and stewarded by CASRAI from that year onward, before NISO formalized it as the ANSI/NISO Z39.104-2022 standard in February 2022 — so that “conceptualization” or “formal analysis” means the same thing from one journal, funder, or CRIS to the next, rather than each publisher maintaining its own incompatible list. CRediT is one implementation of the contributorship idea Rennie, Yank, Emanuel, and Smith argued for in 1997 — not a separate concept.

The two formats you’ll actually encounter

In practice, an author contribution statement takes one of two shapes:

• Free-text / narrative statement. The authors write a short paragraph in their own words describing who did what. No fixed vocabulary, no controlled list — just prose. This remains common outside biomedicine and at journals that never adopted a specific taxonomy.
• Structured / taxonomy-based statement. Each author is mapped to one or more roles drawn from a controlled list — overwhelmingly CRediT in current practice, since it’s the taxonomy most publishers (Elsevier, PLOS, Springer Nature, and others) have standardized submission systems around. See CRediT for authors for the step-by-step and CRediT Author Statement Samples for ready-to-adapt examples across common scenarios (equal contribution, non-author contributors, machine-readable encoding).

A free-text example (non-CRediT format)

Illustrative only — adapt the roles and names to your own paper, not copied from any real published article:

A. Okafor and B. Lindqvist designed the study. B. Lindqvist collected the data. A. Okafor and C. Marsh analyzed the results. A. Okafor wrote the first draft of the manuscript. All authors reviewed the manuscript and approved the final version.

Notice what makes this an author contribution statement rather than a generic disclosure: every sentence attaches an activity to a specific named person, not to “the authors” as an undifferentiated group. A journal that specifies its own fixed category list (design, data collection, analysis, writing, etc., without using CRediT’s exact 14 terms) is still asking for the same underlying thing — this narrative form is what to produce if no taxonomy is specified at all.

Related: Posthumous Authorship — How journals credit a co-author who died before publication: ICMJE’s accountability criteria, COPE’s guidance on corresponding-author attestation, footnote/dagger conventions, and what estate or institutional sign-off actually covers.

A CRediT-taxonomy example

Illustrative only, using CRediT’s standard 14 role terms — not copied from any real published article. This is the same structured format described above, applied to a five-person team where several roles are shared:

Zhang San: Conceptualization, Methodology, Funding acquisition.
Priya Patel: Methodology, Investigation, Resources, Data curation.
Erin Wright: Investigation, Formal analysis, Visualization.
Adam Lloyd: Software, Formal analysis, Validation, Writing – original draft.
Maria García-López: Supervision, Project administration, Writing – review & editing.

Two things this example shows that the free-text version above doesn’t: a role can be shared by more than one author — Methodology and Investigation are each split between two people here — and a single author can carry more than one role, listed in any order after their name. Nothing requires all 14 roles to appear in a given statement; assign only the roles that actually happened. For full role definitions and more ready-to-adapt samples (lead/equal/supporting qualifiers, equal-contribution statements, crediting a non-author contributor), see CRediT Author Statement Samples and the CRediT roles index.

A large multi-author example

Illustrative only, for a ten-person collaborative study — not copied from any real published article. Once an author list runs into double digits, listing every role next to every name individually gets repetitive fast, so many journals and CRIS systems group the statement by role instead, with each role followed by the initials of everyone who performed it:

Conceptualization: W. Chen, F. Al-Sayed.
Methodology: W. Chen, D. Fernández, N. Ibrahim.
Software: L. Andersson.
Validation: D. Fernández, A. Tanaka.
Formal analysis: A. Tanaka, G. Mwangi.
Investigation: F. Al-Sayed, N. Ibrahim, R. Mehta, E. Petrova.
Resources: T. Baker.
Data curation: L. Andersson, R. Mehta.
Writing – original draft: W. Chen, G. Mwangi.
Writing – review & editing: F. Al-Sayed, D. Fernández, E. Petrova, T. Baker.
Visualization: A. Tanaka.
Supervision: W. Chen, T. Baker.
Project administration: N. Ibrahim.
Funding acquisition: T. Baker.

This role-grouped layout carries the same underlying information as the per-author format shown in the five-author example above — just organized the other way round. Some submission systems and CRIS platforms still record it keyed by author internally (one entry per person, with their roles attached) even when the published statement displays role-grouped; if your target journal doesn’t specify a layout, either format is acceptable as long as every role is attached to specific, named individuals rather than to the author group as a whole.

Where it goes, and who checks it

Placement is set by each journal’s own instructions to authors, but the statement is conventionally positioned after the main text (after the discussion or conclusion) and before acknowledgments, funding statements, conflict-of-interest disclosures, and references. As with authorship itself, ICMJE places responsibility for the accuracy of a contribution statement on the author group, not the journal — see ICMJE Authorship Criteria for how that same principle applies to who counts as an author in the first place. Corresponding authors typically coordinate collecting and confirming each co-author’s statement before submission; see Corresponding Author Responsibilities.

Frequently asked

Is an author contribution statement the same as a CRediT statement?

No — CRediT is one specific, standardized way to write an author contribution statement. Every CRediT statement is an author contribution statement, but not every author contribution statement uses CRediT; plenty of journals still accept or require a free-text paragraph instead.

Do all journals require one?

No. ICMJE encourages but does not mandate contributorship statements, so requirements vary by journal and by publisher. Check the specific journal’s instructions to authors before submission.

Can I write an author contribution statement without using CRediT?

Yes, unless the target journal specifically requires CRediT. A free-text paragraph naming each author’s individual role is a valid contribution statement in its own right — see the example above.

What’s the difference between a contribution statement and authorship criteria?

Authorship criteria (ICMJE’s four-part test) determine who qualifies to be listed as an author at all. A contribution statement is a separate, additional disclosure written after that list is settled, describing what each already-qualified author did. See ICMJE Authorship Criteria.

Where do non-author contributors go?

People who helped but don’t meet authorship criteria (e.g., a medical writer, a technician who ran an assay, someone who provided reagents) are acknowledged separately, not listed as authors or folded into the contribution statement’s author list. See non-author contributor.

Related CASRAI resources

• CRediT Author Statement Samples — ready-to-adapt CRediT-taxonomy statements for common scenarios
• CRediT for authors — step-by-step guide to writing a CRediT contributor statement
• ICMJE Authorship Criteria — the four-part test for who qualifies as an author
• Corresponding Author Responsibilities
• Resolving Authorship Order Disputes
• Non-author contributor
• Ghost authorship
• Gift authorship
• “Degree of contribution” qualifier (lead/equal/supporting)
• ICMJE (International Committee of Medical Journal Editors)
• CRediT (Contributor Roles Taxonomy) — the 14-role standard, maintained by CASRAI
• CRediT author statement samples — the structured form, for journals that require CRediT
• CRediT & Authorship Attribution — cluster hub

Contribution statements are harder to write under corporate authorship, where no individual is named.