The ICMJE requires clinical trial manuscripts to carry a data sharing statement declaring whether individual participant data (IPD) will be shared, what data, when, and under what access conditions — but it does not require the data itself to be shared. Journals then layer their own rules on top of this baseline, and those rules diverge sharply: some merely echo ICMJE wording, others (notably The BMJ) mandate deposit at publication. A data sharing statement is a structured declaration, published alongside a clinical trial report, that specifies the existence, location and access terms of the underlying participant-level dataset.
- What does ICMJE actually require?
- How do journal policies diverge from the ICMJE baseline?
- The five elements a compliant statement must address
- The 2019 trial-registration rule authors often miss
- Common questions about ICMJE data sharing statements
- What this means for authors, editors and institutions
What does ICMJE actually require?
The International Committee of Medical Journal Editors’ Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals has required a data sharing statement for every clinical trial manuscript since 1 July 2018. The requirement is definitional, not aspirational: manuscripts reporting a clinical trial must include a statement addressing data sharing plans, and this statement must be included in the registered trial record for trials that began enrolling participants on or after 1 January 2019.
Crucially, ICMJE does not mandate that IPD actually be shared. It mandates transparent disclosure of the sharing plan — including a legitimate “no” — so that readers, editors, and future researchers know exactly what to expect from a given trial’s dataset. This distinction is the single most misunderstood point in author guidance, and it is the reason journal policies vary so widely: ICMJE sets a disclosure floor, not a sharing floor.
How do journal policies diverge from the ICMJE baseline?
Most general medical journals state that they “follow” or “endorse” ICMJE recommendations, but the practical requirements imposed on authors range from a simple declaration to a binding deposit obligation. The table below compares four ICMJE-member journals against the ICMJE baseline itself.
| Source | Declaration required | IPD sharing mandatory | Typical timing |
|---|---|---|---|
| ICMJE baseline | Yes — five-element statement | No — disclosure only | Plan filed at trial registration (trials enrolling from 1 Jan 2019) |
| The BMJ | Yes, plus analysis code | Yes, for Tier 1 journals — anonymised IPD required at publication (from 1 May 2024) | At time of publication |
| The Lancet | Yes, endorses ICMJE wording | No — encouraged via controlled access | Commonly from 2 years post-publication, no fixed end date |
| NEJM | Yes — plan filed with submission | No — favours sharing with data scientists on request | Set out in the filed plan |
| JAMA Network | Yes — extended to all research reports, not only trials | No — stated intent does not affect editorial decisions | Author-defined |
The practical effect is a compliance gradient. An author who has met ICMJE’s disclosure requirement has not automatically met The BMJ’s Tier 1 deposit requirement, and a statement accepted by JAMA for a non-trial research report would not necessarily satisfy the trial-specific registration rule that ICMJE applies only to clinical trials.
The five elements a compliant statement must address
Journal submission systems increasingly convert free-text author input into a structured statement. Whatever the interface, ICMJE guidance implies five elements that a clinical trial data sharing statement should cover:
- Whether individual de-identified participant data will be shared — a definite yes or no, not a hedge.
- What data will be shared — the full dataset, specific variables, or statistical code.
- Related documents — whether the protocol, statistical analysis plan, or informed-consent form will also be made available.
- When access begins and ends — a start date and, where relevant, an end date or “no end date” statement.
- Access criteria — who may request the data, for what purposes, and through which mechanism (repository, data access committee, or corresponding-author request).
Omitting any one of these five elements is the most common reason editorial offices return a “data availability statement” for revision before it can proceed to peer review.
The 2019 trial-registration rule authors often miss
ICMJE’s registration requirement is easy to overlook because it sits upstream of manuscript submission. For any trial that began enrolling participants on or after 1 January 2019, the data sharing plan must appear in the trial’s registry record itself — for example on ClinicalTrials.gov — not only in the eventual manuscript. If the plan changes between registration and publication, ICMJE requires the change to be noted in both the published statement and the registry record.
Authors who register a trial without a data sharing field, then attempt to add a compliant statement only at manuscript submission years later, frequently discover that the registry record cannot be reconciled retrospectively without a formal amendment. This is a process failure, not a wording failure, and it is the single largest source of avoidable non-compliance in the studies CASRAI has reviewed.
Common questions about ICMJE data sharing statements
How to write a data sharing statement?
State clearly whether individual participant data will be shared, what data and related documents are included, when access opens (and closes, if applicable), and the access criteria and mechanism. Draft the wording to match your target journal’s submission-system prompts, since most convert structured answers directly into the published statement.
What is an example of a data access statement?
A typical ICMJE-compliant example: “De-identified individual participant data will be available beginning two years after publication, with no end date, to researchers who provide a methodologically sound proposal, via [named repository].” This single sentence satisfies the what, when, and access criteria elements ICMJE expects.
What is the meaning of data statement?
A data statement — also called a data availability statement or data sharing statement — is a published declaration specifying whether the data underlying an article exists, where it is held, and how another researcher can obtain it. For clinical trials, ICMJE requires this declaration to cover five specific elements, not a general availability claim.
What are the three types of data sharing?
In scholarly publishing, the response types an ICMJE-compliant statement typically selects from are: open deposit in a public repository, controlled access through a data access committee, and sharing on reasonable request to the corresponding author. Each carries different timing and access-criteria wording under the five-element framework.
What this means for authors, editors and institutions
For corresponding authors, the practical task is twofold: satisfy ICMJE’s disclosure floor at registration and manuscript stages, then check the target journal’s own tier or policy for anything stricter — deposit timing, code-sharing, or scope beyond trials. Research administration offices supporting authorship and compliance workflows are well placed to build this check into pre-submission review, since the registration-stage requirement is easy to miss and hard to fix after the fact.
As more journals move toward BMJ-style mandatory deposit, the gap between the ICMJE floor and individual journal ceilings is likely to widen rather than close. Authors, institutions and publishers should treat the ICMJE statement as the minimum compliance baseline, not the finish line, and verify journal-specific requirements — ideally cross-checked against a standards dictionary entry — before submission rather than after a revision request.
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