A large randomised clinical trial is one of the most collaborative undertakings in research. A single phase III study can involve hundreds of investigators across dozens of sites, plus statisticians, data managers, monitoring committees, and the coordinating centre that holds it all together. Yet the article that reports the result carries a byline that may name only a dozen people. How can a byline that small honestly represent an effort that large? The answer lies in a set of conventions — the ICMJE authorship criteria, group authorship, and a structured contributions statement — that together let a vast, distributed effort be recorded fairly without diluting accountability. This sits squarely in the territory the guidance on group authorship addresses, and it leans heavily on the CRediT roles to do the fine-grained work.
The ICMJE authorship criteria
The reference point for who counts as an author of a clinical trial is the International Committee of Medical Journal Editors (ICMJE). The ICMJE recommendations set out four criteria, all of which an individual must meet to qualify for authorship:
- Substantial contributions to the conception or design of the work, or the acquisition, analysis, or interpretation of data;
- Drafting the work or revising it critically for important intellectual content;
- Final approval of the version to be published; and
- Agreement to be accountable for all aspects of the work, ensuring that questions about its accuracy or integrity are appropriately investigated and resolved.
The fourth criterion is the one most often forgotten and the most important: authorship is not only credit, it is responsibility. Crucially, the ICMJE is explicit that contributors who meet criterion 1 but not all four should not be authors — they should be acknowledged instead. This is what prevents a trial byline from simply listing everyone who collected data at a site, and it is also why “gift” authorship of senior figures who did not meet the criteria is a breach of the standard rather than a courtesy.
Group authorship: naming the collaboration
The criteria create an obvious tension in large trials. Hundreds of people made genuine, substantial contributions, but they cannot all meet every criterion, and a byline of three hundred names would be unusable. Group authorship is the ICMJE-sanctioned solution. A trial is published under the name of the study group — for example, “the EXAMPLE-2 Trial Investigators” — and the article distinguishes between two categories of people:
- Named authors who individually meet all four ICMJE criteria and take direct responsibility for the manuscript. These may be listed in the byline alongside the group name, or the group name itself may carry the authorship with the qualifying individuals identified.
- Collaborators — the wider membership of the study group who contributed substantially to the trial but do not individually meet all four authorship criteria. They are listed by name, typically in an appendix or supplementary file, and are indexed by databases such as PubMed as collaborators rather than authors.
This is not a way of demoting people. It is a way of telling the truth about a collaboration: a clear, public record that this person was a named author who is accountable for the paper, and that person was a collaborating investigator whose site recruited patients and whose work made the trial possible. The ICMJE asks that the journal specify, somewhere in the article, exactly who is responsible in each category, so that the byline cannot be read as either inflating or erasing anyone’s role.
The CRediT statement: who did what
Group authorship answers who is accountable; it does not, by itself, answer who did what. That is the job of a structured contributions statement built on the CRediT taxonomy. CRediT supplies fourteen standard roles — Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization, Supervision, Project administration, and Funding acquisition — and a clinical trial maps onto them unusually cleanly:
- Conceptualization and Methodology capture the people who designed the trial and its protocol.
- Investigation records the site investigators who recruited and assessed participants — the role that most collaborating investigators occupy.
- Data curation records the data managers who cleaned and maintained the trial database.
- Formal analysis records the statisticians who ran the pre-specified analyses.
- Project administration records the coordinating-centre staff who ran the trial day to day.
- Funding acquisition records those who secured the grant that paid for it.
A CRediT statement turns the contributions section from a vague paragraph of thanks into machine-readable data. For a named author it can specify a degree of contribution — lead, equal, or supporting — so that the chief investigator’s role in Conceptualization is distinguished from a co-author’s supporting role. Used well, it means that a reader, a hiring committee, or a CRIS system can see precisely how the labour of a trial was divided, rather than inferring it from author order alone.
Why this matters for accountability
Clinical trials carry unusual weight: their results change clinical practice and affect patients. That raises the stakes of the fourth ICMJE criterion. When questions are later raised about a trial — a data discrepancy, an unreproducible analysis, a query about a particular site — the structured record of authorship and contribution is what makes accountability tractable. Knowing who took responsibility as a named author, who curated the data, and who ran the statistics localises responsibility rather than diffusing it across an anonymous group. A trial that is published under a study-group name and carries both a clear statement of named authors and a CRediT breakdown is far more accountable than one with a long, undifferentiated byline.
Practical guidance for trial teams
- Decide authorship against the ICMJE criteria, not seniority or site. Meeting criterion 1 alone makes someone a collaborator, not an author.
- Adopt a group name and a written authorship policy early — ideally in the protocol — so that expectations are set before the data exist and disputes are pre-empted.
- List collaborators by name. Being a collaborating investigator is a real, indexed, citable contribution; do not bury it.
- Publish a CRediT statement mapping each named author to their roles, with degree-of-contribution where it clarifies who led what.
- Attach ORCID iDs to named authors and, where possible, collaborators, so that the contribution propagates to each person’s record rather than being lost to a generic group name.
Where shared vocabulary fits
“Author”, “collaborator”, “investigator”, “study group”, and “contributor” are used inconsistently across trials and journals, which is part of why trial bylines are so often misread. A shared, federated vocabulary that defines these terms precisely — and points back to the ICMJE recommendations and the CRediT taxonomy — is what lets a group-authored trial in one journal be understood the same way in another. Supplying that definitional layer is the role the CASRAI dictionary is designed to play.