NEJM Formatting Requirements: Complete Author Guide

NEJM's abstract requirements are precise and editors screen them carefully.

• 250 words maximum with four required headings: Background, Methods, Results, Conclusions
• Conclusions must be clinical interpretation, not a restatement of results. What should doctors do differently? If your Conclusions reads like compressed Results, it needs rewriting.
• Trial registration number (ClinicalTrials.gov) must appear at the end of the abstract for all clinical trials
• "Funded by" line appears after the abstract, before the main text. This is a fixed structural element, not a footnote. It's separate from the 250-word count.
• No citations permitted in the abstract
• No keywords required. NEJM assigns MeSH indexing internally.

The 4-display-item cap is where NEJM formatting becomes genuinely strategic. A clinical trial needing a CONSORT flow diagram and a Kaplan-Meier curve has already used half its budget.

Table rules: No vertical rules. Horizontal rules only at top, below headers, and at bottom. Every column needs a header. Baseline characteristics tables should show treatment groups side by side, and p values generally should not appear in baseline tables.

NEJM redraws all accepted figures. Their art department recreates every figure to match the journal's house style, different colors, fonts, and layout. Your submission figures must contain all necessary data and labeling, but they don't need to match NEJM's exact published look.

NEJM uses Vancouver-style numbered references with superscript in-text citations (e.g., "as previously reported^1,2"), numbered in order of first appearance.

1. Author AB, Author CD, Author EF, et al. Title of article. Journal Abbrev Year;Volume:Pages.

Specifics that trip people up:

• List up to 20 authors before "et al." (more generous than The Lancet's 6-author limit)
• No periods after author initials
• Journal names abbreviated per MEDLINE/NLM standards
• No issue numbers for most journals
• DOI required for online-ahead-of-print or online-only articles
• Personal communications go in parentheses in the text (with written permission), not the reference list
• References to retracted articles must be labeled "[Retracted]" after the title, NEJM editors check this during production

The 40-reference cap still requires careful curation. Every reference should directly support a specific claim.

NEJM requires a detailed title page with elements many authors forget:

• Title: Concise, no abbreviations. For trials, include study design: "Drug X versus Placebo for Condition Y: A Randomized Controlled Trial."
• Author names with degrees: Full names plus highest academic degrees (MD, PhD, MPH). NEJM is one of the few top journals that requires degrees on the byline.
• Institutional affiliations, corresponding author contact (postal address, email, phone, fax), word counts (body and abstract listed separately), and number of display items
• Funding listed on title page in addition to the "Funded by" abstract line
• Trial registration number for all clinical trials

Conflict of interest forms: All authors must complete disclosure forms via Convey (NEJM's COI platform). Forms must be current within the previous 12 months. NEJM helped create the ICMJE disclosure framework, and compliance is verified before any manuscript enters review. This applies to every author, not just the corresponding author.

Author contributions: A statement describing each author's role is required, following ICMJE criteria: (1) substantial contributions to conception/design or data acquisition/analysis, (2) drafting or critical revision, (3) final approval, and (4) accountability for the work.

This is where many technically sound manuscripts fail at NEJM.

Statistical analysis plan (SAP): Required for all clinical trials, finalized before database lock, published in the Supplementary Appendix. NEJM requires documentation that the SAP was locked before the database was unblinded. Submitting without this documentation will trigger editorial queries.

Independent statistical review: For industry-sponsored trials, NEJM may require an independent academic statistician (not employed by the sponsor) to verify the primary analysis. This requirement has caught many industry submissions off guard, budget for it early.

Reporting rules:

• All p values must be two-sided and exact (p=0.03, not p<0.05)
• 95% confidence intervals preferred over p values for treatment effects
• Multiple-comparison corrections (Bonferroni or equivalent) must be applied and explained
• Intention-to-treat analysis is the primary analysis for randomized trials
• CONSORT compliance and flow diagram required for all RCTs (the flow diagram counts as one display item)
• STROBE for non-randomized studies, PRISMA for systematic reviews

Study registration check: NEJM screens every manuscript at submission to determine whether the study required prospective registration. No manuscript enters the editorial process until it passes this screen. If your trial should have been registered and wasn't, the paper is dead on arrival.

The NEJM author center gives you the rules. Here's what it doesn't emphasize:

The desk rejection rate is high and fast. NEJM rejects most manuscripts within one week of submission, before peer review. The initial editorial screen evaluates novelty, clinical impact, and formatting. A perfectly formatted paper on a low-impact topic still gets desk-rejected. But a high-impact paper with sloppy formatting also gets desk-rejected, and that's the preventable failure.

Conventional units first. NEJM uses conventional units for lab values (mg/dL, cells/mm^3) with SI units in parentheses. The Lancet does the opposite. Getting this wrong won't trigger rejection alone, but it signals unfamiliarity with the journal.

Published articles routinely exceed word limits. Research shows published NEJM articles exceed the stated 2,700-word limit by roughly 25%. This suggests some flexibility exists post-acceptance, but you should still submit at or under the limit. Editors won't extend you that courtesy before they've decided to publish your paper.

Editorials accompany accepted articles. NEJM commissions an independent editorial to publish alongside your Original Article. You don't write it, but the editorial author receives your manuscript in advance. This adds to the timeline between acceptance and publication.

LaTeX is technically accepted but practically irrelevant. Over 95% of NEJM submissions are in Word. NEJM provides a Word template but no LaTeX template. If you use LaTeX, ensure your BibTeX outputs Vancouver-style references using vancouver.bst.

Proof review is author-responsible. NEJM provides page proofs and holds authors accountable for errors that survive to publication. Check every number, every confidence interval, every p value. The journal's position is explicit: factual errors in the published version are the authors' problem if they weren't caught during proofing.

No graphical abstract. Unlike Cell (where it's mandatory), NEJM does not use graphical abstracts. Don't submit one, it signals unfamiliarity with the journal.

AI interventions in clinical trials. For trials that began enrolling after January 1, 2025, NEJM requires that AI interventions meet the same evidence bar as any other clinical intervention. This means prospective registration, a pre-specified SAP, and standard reporting. The policy doesn't affect manuscripts about AI methods in general, it's specific to trials using AI as part of patient care.

The Supplementary Appendix is reviewed. Unlike some journals where supplements are barely glanced at, NEJM's Supplementary Appendix goes through full peer review. For major trials, it often runs 20--60 pages and must include the trial protocol and SAP.

The Supplementary Appendix is where most of your detailed work lives at NEJM, and it's more structured than at other journals.

Required contents for clinical trials:

• Extended methods (detailed protocol)
• Statistical analysis plan (the version finalized before database lock)
• Supplementary tables (Table S1, S2, etc.) and figures (Figure S1, S2, etc.)
• Additional results, subgroup analyses, sensitivity analyses
• Full trial protocol (the final IRB/ethics-committee-approved version)

Formatting: Compiled as a single PDF with internal pagination starting at page 1. If longer than 10 pages, it must include a table of contents. The appendix must be submitted in both PDF and an editable format (Word).

Data sharing statement: NEJM requires a data sharing statement for all clinical trials. The statement must specify what data will be available, to whom, for what types of analyses, and by what mechanism (NEJM's own data sharing platform or an established repository). This isn't optional, manuscripts without a data sharing plan will trigger editorial queries.

The Supplementary Appendix is also where you recover from the 4-display-item limit. Supplementary figures and tables don't count toward the cap in the main text, so plan your display strategy across both the main manuscript and the appendix.

In our pre-submission review work with manuscripts targeting the New England Journal of Medicine, four patterns generate the most consistent desk-rejection outcomes.

Abstract exceeds 150 words or is not structured with the NEJM-required headings. NEJM Original Articles require a structured abstract of no more than 150 words with the following headings: Background, Methods, Results, and Conclusions. Unlike Lancet Group journals, NEJM uses "Results" and "Conclusions," not "Findings" and "Interpretation." Manuscripts submitted with unstructured abstracts, with alternative heading terminology, or with abstracts over 150 words are returned for correction at the editorial office stage. This is one of the most common and avoidable submission errors.

Reporting guideline documentation missing. NEJM requires completed reporting checklists for all clinical study types: CONSORT for randomized trials, STROBE for observational studies, PRISMA for systematic reviews, and STARD for diagnostic accuracy studies. The checklist must be submitted as a separate file and is verified by the editorial office before the paper is forwarded for consideration. Manuscripts that arrive without the appropriate checklist are asked to resubmit. NEJM editors treat this as evidence of whether the reporting is complete, not just a formality.

Primary endpoint analysis not pre-specified or inconsistent with the registered protocol. NEJM statistical reviewers compare the stated primary endpoint in the manuscript against the trial registration record (ClinicalTrials.gov, WHO ICTRP, or EudraCT). Manuscripts where the primary endpoint analyzed differs from the registered primary endpoint without transparent explanation, or where a secondary endpoint is presented as equivalent to the primary, are flagged for statistical review before peer review. NEJM publishes the trial registration number alongside the article and expects full consistency.

Clinical significance framing applies to a narrow specialty population. NEJM publishes findings "of major importance to clinical medicine." Submissions whose clinical implications are meaningful primarily to subspecialists in one narrow field, rather than to the broad readership of practicing clinicians across disciplines, are declined at the desk-review stage. Editors assess whether a primary care physician, hospitalist, or clinician in a non-specialist setting would change practice based on the study's findings.

A NEJM formatting and readiness check evaluates manuscript structure, abstract compliance, trial registration consistency, and clinical significance framing against these desk-rejection patterns before you submit.