NEJM Formatting Requirements: Complete Author Guide

NEJM's structured abstract is a model of clinical reporting clarity.

• Word limit: 250 words maximum
• Structure: Four required headings:
• Background: The clinical question and rationale (2-3 sentences)
• Methods: Study design, setting, patients, intervention, and primary outcome
• Results: Main findings with effect sizes, confidence intervals, p values
• Conclusions: Clinical meaning of the findings (not a restatement of results)
• Trial registration: For clinical trials, the ClinicalTrials.gov number must appear at the end of the abstract
• Funded by: A separate line after the abstract stating the funding source
• Citations: Not permitted in the abstract
• Keywords: Not required. NEJM assigns MeSH indexing internally.

NEJM editors pay particular attention to the Conclusions section of the abstract. It shouldn't be a restatement of the Results. It should provide a clinical interpretation: what should doctors do differently based on these findings? If your Conclusions section reads like a compressed version of your Results, it needs rewriting.

The "Funded by" line is mandatory and appears after the Conclusions but before the main text begins. It's separate from the 250-word count.

NEJM's 4-item cap on display items is the tightest among the journals covered in this guide.

With only 4 display items, strategic figure planning matters more at NEJM than at almost any other journal. A clinical trial with a CONSORT flow diagram (often required) and a Kaplan-Meier curve has already used 2 of 4 slots.

Table formatting: NEJM has specific table style requirements:

• No vertical rules
• Horizontal rules only at top, below headers, and at bottom
• Every column must have a header
• Baseline characteristics tables (Table 1 in most clinical trials) should show treatment groups side by side
• P values should generally not appear in baseline characteristics tables (unless relevant to the study question)

NEJM figure style: NEJM's art department redraws all accepted figures to match the journal's house style. You submit your best version, but the published figures will look different. They'll use NEJM's color palette, font choices, and layout conventions. This means you don't need to match NEJM's exact style at submission, but your figures must contain all the necessary data and labeling for the art department to work from.

Interactive figures: NEJM increasingly publishes interactive figures for its online version (e.g., interactive forest plots, dynamic Kaplan-Meier curves). If your data supports interactivity, discuss this with the editorial office at the revision stage.

NEJM uses Vancouver-style numbered references, similar to The Lancet.

In-text citations: Superscript numbers (e.g., "as previously reported^1,2"). Numbered in order of first appearance.

Reference list format:

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

Key formatting details:

• List up to 20 authors before using "et al." (NEJM is 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
• Year followed by semicolon, volume, colon, pages
• DOI included for online-ahead-of-print or online-only articles
• Personal communications: cited in parentheses in the text with written permission, not in the reference list
• Unpublished data: cited in the text as "(unpublished data)" with no reference list entry

The reference cap for Original Articles is 40, which is more generous than The Lancet's 30 but still requires careful curation. Every reference should directly support a specific claim in the text.

NEJM-specific detail: references to retracted articles must be labeled. If you cite a paper that was later retracted, add "[Retracted]" after the title. NEJM editors check for this during production.

NEJM calls its supplementary content the "Supplementary Appendix."

Supplementary Appendix contents:

• Extended Methods (detailed protocol, statistical analysis plan)
• Supplementary tables (labeled Table S1, S2, etc.)
• Supplementary figures (labeled Figure S1, S2, etc.)
• Additional results (subgroup analyses, sensitivity analyses)
• Trial protocol (required for all clinical trials)
• Statistical analysis plan (required for clinical trials)
• ICMJE disclosure forms (submitted separately but considered part of the supplement)

Formatting:

• Compiled as a single PDF
• Internal pagination starting at page 1
• Must include a table of contents if longer than 10 pages
• Goes through full peer review

Protocol and SAP publication: For clinical trials, NEJM publishes the full trial protocol and statistical analysis plan as part of the Supplementary Appendix. These documents are available to readers and are considered part of the published record. The protocol must be the final version approved by the IRB/ethics committee, and the SAP must be the version that was finalized before database lock.

Data sharing: NEJM requires a data sharing statement. For clinical trials, NEJM supports data sharing through the NEJM Data Sharing platform or established repositories. The statement specifies what data will be available, to whom, and under what conditions.

NEJM's Supplementary Appendix often runs 20-60 pages for major clinical trials. There's no formal page limit, but everything in the appendix should be directly relevant to the main paper.

NEJM requires a detailed title page.

Title page elements:

• Title: Concise, descriptive, no abbreviations. For clinical trials, include the study design: "Drug X versus Placebo for Condition Y: A Randomized Controlled Trial."
• Author names and degrees: Full names with highest academic degrees (MD, PhD, etc.). NEJM is one of the few journals that requires degrees to be listed.
• Institutional affiliations: Department, institution, city, state/country.
• Corresponding author: Full postal address, email, phone, fax.
• Word count: Listed explicitly (body text and abstract separately).
• Number of display items: Listed explicitly.
• Support/funding: Listed on the title page in addition to the "Funded by" abstract line.
• Trial registration number: ClinicalTrials.gov identifier for all clinical trials.

ICMJE Forms: All authors must complete the ICMJE Uniform Disclosure Form for Potential Conflicts of Interest. This is non-negotiable. Forms must be completed within the previous 12 months. NEJM helped create the ICMJE disclosure framework, and compliance is verified before any manuscript proceeds to review. You can download the form from the ICMJE website.

Author contributions: NEJM requires a statement describing each author's contribution. The journal follows ICMJE authorship criteria strictly: (1) substantial contributions to conception/design or data acquisition/analysis, (2) drafting or critical revision, (3) final approval, and (4) accountability for the work.

NEJM has stricter statistical reporting requirements than most journals, and this is an area where many manuscripts fail.

Statistical analysis plan (SAP): Required for all clinical trials. Must be finalized before database lock. Published as part of the Supplementary Appendix.

Independent statistical review: NEJM frequently requests that the statistical analysis be independently verified. For industry-sponsored trials, NEJM may require that an independent academic statistician (not employed by the sponsor) verify the primary analysis. This requirement has caught many industry submissions off guard.

Specific reporting requirements:

• All p values must be two-sided
• Confidence intervals (95%) are preferred over p values for treatment effects
• Exact p values should be reported (e.g., p=0.03), not inequality thresholds (p<0.05)
• Bonferroni or other multiple-comparison corrections must be applied and explained when applicable
• Intention-to-treat analysis is the primary analysis for randomized trials
• Sensitivity analyses should test whether findings hold under alternative assumptions

Trial reporting: CONSORT compliance is mandatory for all randomized trials. The CONSORT flow diagram is required and counts as one of your 4 display items. For non-randomized studies, STROBE compliance is expected. For systematic reviews, PRISMA is required.

These are the details that experienced NEJM authors know:

Author degrees on the byline. NEJM lists author degrees (MD, PhD, MPH, etc.) next to names in the published article. This is unusual among top journals. Submit the correct degrees for all authors at the initial submission to avoid production delays.

NEJM redraws all figures. Unlike most journals that use author-submitted figures as-is (with minor adjustments), NEJM's art department redraws every figure from scratch to match the journal's visual style. Submit clean, well-labeled source figures with all data clearly indicated. The published version will look different but contain the same information.

The "Funded by" line is structural. This line appears between the abstract and the main text and is visible in every format (print, HTML, PDF). It's not a footnote or acknowledgment. It's a fixed structural element of every NEJM Original Article. Don't bury funding information only in the Acknowledgments.

Editorials accompany major articles. If your Original Article is accepted, NEJM will typically commission an independent editorial that publishes alongside it. You don't write this editorial, but knowing it exists helps you understand the publication timeline. The editorial author receives your manuscript in advance and may contact you with questions.

Proof review is author-responsible. NEJM provides page proofs and expects careful author review. The journal makes this clear: factual errors that survive to publication because authors didn't catch them during proofing are the authors' responsibility. Check every number, every CI, every p value in proofs.

Conventional units first. NEJM uses conventional units for laboratory values (mg/dL, cells/mm^3), with SI units in parentheses. This is the opposite of The Lancet, which prefers SI units first. Getting this wrong won't trigger rejection, but it marks you as unfamiliar with the journal.

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

Video abstracts. NEJM increasingly features video summaries of major articles, produced by the NEJM media team. Authors may be invited to participate in a video interview for their paper. This is arranged post-acceptance and is optional.

1. ICMJE forms for every author. Not just the corresponding author. Every person listed as an author must submit a completed ICMJE disclosure form. Missing forms will delay processing.

1. Degrees on the title page. Include the highest academic degree for each author (MD, PhD, ScD, etc.). NEJM requires this and will request it if omitted.

1. CONSORT flow diagram counts as a display item. Plan your 4-item budget knowing that clinical trials almost always need a flow diagram.

1. ClinicalTrials.gov number in the abstract. For trials, the registration number must appear at the end of the abstract, not just on the title page.

1. Statistical analysis plan finalized before unblinding. For randomized trials, NEJM requires documentation that the SAP was locked before the database was unblinded. Submitting without this documentation will trigger editorial queries.

1. Double-spacing and line numbers. Required for the review manuscript. Submissions without line numbers make it harder for reviewers and will be returned.