JAMA Formatting Requirements: Complete Author Guide

JAMA requires structured abstracts for Original Investigations and Reviews. An Original Investigation abstract can't exceed 350 words and must use the headings JAMA lists, in this order:

For Original Investigations, the structured abstract uses these exact headings in this order:

This is where many authors slip up. JAMA doesn't use the standard IMRAD abstract structure that most journals accept. If you submit with "Background" instead of "Importance" or "Conclusions" instead of "Conclusions and Relevance," you'll get sent back for reformatting.

The Importance section should be 1-2 sentences establishing why this research matters clinically. Don't waste space on broad epidemiological context that reviewers already know. The Conclusions and Relevance section must directly address the clinical implications, not just restate results.

JAMA requires a title page as the first page of your manuscript. It must include:

• Full manuscript title (no abbreviations allowed in the title)

• All author names with highest academic degrees

• Institutional affiliations for each author

• Corresponding author name, address, phone, and email

• Manuscript word count (not including title, abstract, acknowledgment, references, tables, and figure legends)

One quirk that catches people: JAMA wants each author's highest academic degrees listed on the title page.

JAMA permits a maximum of 5 display items (figures and tables combined) for an Original Investigation. Additional material can go in the online-only supplement, which JAMA says should be limited and justified.

Figure requirements:

• Required minimum resolution for publication: 350 ppi for photographs and illustrations, 600 ppi for line drawings

• Accepted formats depend on the figure type; for revision and publication, JAMA lists .ai, .emf, .eps, .pdf, .wmf, and .xls for graphs and .eps, .jpg, .psd, and .tif for photographs

• Upload each figure as a separate file (JAMA allows figures appended to the manuscript at first submission, but requires separate files if a revision is requested)

Table requirements:

• Tables must be created in Word using the table function (not as images)

• Tables need at least 2 columns, and comparisons must read across the table columns

• Do not draw extra lines or rules; the table grid displays the outlines of each cell

• Abbreviations in tables must be defined in footnotes

• P values follow JAMA's decimal-place conventions (P<.001 below .001, the nearest thousandth from .001 to .01, the nearest hundredth from .01 up)

JAMA asks authors to avoid complex composite or multipart figures unless justified, and not to submit figures with more than 4 panels unless justified, so do not count on multipanel figures to stay under the 5-item limit.

JAMA follows the AMA Manual of Style, 11th edition. This is non-negotiable, and it's different enough from Vancouver style that you can't just use "close enough" formatting.

Key AMA reference rules:

• Citations appear as superscript numbers in the text, placed after punctuation

• References are numbered consecutively in order of first citation

• List all authors when there are 6 or fewer; for 7 or more, list the first 3 followed by "et al"

• Journal names are abbreviated according to NLM standards

• Include the issue number in parentheses after the volume number for journal references

Worked example (AMA 11th edition, with the common wrong form shown for contrast):

Correct (AMA): Smith AB, Jones CD, Williams EF. Association of sleep duration with mortality in older adults. *JAMA*. 2026;**335**(4):412-420. doi:10.1001/jama.2026.1234
Wrong (Vancouver/APA preset most reference managers default to): Smith, A. B., Jones, C. D., & Williams, E. F. (2026). Association of sleep duration with mortality.

JAMA, 335(4), 412-420.

The difference is exactly what trips up auto-exported bibliographies: AMA writes "Smith AB" with no commas or periods inside the name, abbreviates the journal per NLM, and uses superscript citation numbers; the Vancouver/APA form your reference manager exports by default uses "Smith, A. B." and is wrong for JAMA.

Example book chapter reference (AMA):

Johnson KL. Clinical pharmacology. In: Roberts MN, ed. *Handbook of Internal Medicine*. 5th ed. Elsevier; 2025:142-168.

Most reference managers handle AMA style reasonably well, but always manually check for the author cutoff rule and issue number inclusion. These are the two most common errors in JAMA reference formatting.

JAMA's instructions call this the online-only supplement and number its items with an "e" prefix. Online-only content is peer-reviewed with the main manuscript and published online only.

Your eSupplement should be compiled into a single document with the following structure:

• eMethods: Additional methodological details

• eFigures: Numbered sequentially (eFigure 1, eFigure 2, etc.)

• eTables: Numbered sequentially (eTable 1, eTable 2, etc.)

• eReferences: All references cited within the eSupplement, including any also cited in the main manuscript

Each element in the eSupplement must be cited in the main manuscript text. Don't dump extra data into the eSupplement without referencing it. The prefix "e" is required for all supplementary items. Write "eTable 3" in your manuscript, not "Supplementary Table 3."

JAMA does not publish a word limit for the online-only supplement, but says the amount should be limited and justified. If your eSupplement is longer than your main manuscript, consider whether some of that material should be in the main text instead, or whether it's truly necessary.

JAMA has several formatting rules that differ from other major medical journals. Missing these is a common source of administrative returns.

1. The "Importance" heading in abstracts. Most medical journals use "Background" or "Introduction." JAMA uses "Importance." This isn't optional.

2. Statistical reporting requirements. JAMA sets specific P value conventions: report P<.001 for values below .001, the nearest thousandth for values from .001 to .01, and the nearest hundredth for values of .01 or above (P =.03, not P <.05). It also asks for confidence intervals alongside absolute numbers or rates, and says P values should never be presented alone without the data being compared.

3. No abbreviations in the title. Unlike many journals that allow common abbreviations (RCT, BMI, CI), JAMA prohibits all abbreviations in the manuscript title. Spell everything out.

4. Conflict of interest and funding placement. JAMA requires conflict of interest disclosures and funding information at the end of the manuscript, before references. They also go in the Authorship Form that JAMA emails to every author after submission, and they appear in the published article.

5. Key Points box. Original Investigations must include a "Key Points" box with three elements: Question (1 sentence), Findings (2 sentences max), and Meaning (1 sentence). This appears at the beginning of the published article and is one of the most-read sections.

6. Author contributions. JAMA requires authors to identify their specific contributions to the work through the Authorship Form that is emailed to all authors after submission.

The body of a JAMA Original Investigation typically follows this structure:

1. Introduction (keep it short)

1. Methods (including study design, setting, participants, interventions, outcomes, statistical analysis)

1. Results (organized to match the Methods section)

1. Discussion (interpret findings, compare with existing literature, discuss limitations, state conclusions)

Keep the Introduction brief: identify the gap in knowledge and state the study objective. Don't provide an exhaustive literature review. Save the context for the Discussion.

The Methods section must include an ethics statement specifying IRB approval and informed consent procedures. For clinical trials, the registry name, registration number, and URL are required at the end of the abstract.

For manuscripts targeting JAMA, four patterns generate the most consistent desk-rejection outcomes.

Structured abstract uses wrong JAMA network headings. JAMA requires specific structured abstract headings: Importance, Objective, Design, Setting, Participants, Interventions (trials) or Exposures (observational studies), Main Outcomes and Measures, Results, and Conclusions and Relevance. Papers using generic clinical headings (Background, Methods, Results) are returned before peer review. The "Importance" section must state the clinical significance in 1-2 sentences; the "Conclusions and Relevance" must include a direct clinical implication.

Study does not meet the population-level or practice-changing threshold. JAMA's editorial standard requires research that changes what clinicians do or what patients should know, at scale. Papers reporting a novel finding in a small referral-center cohort, or a treatment comparison without adequate power for definitive conclusions, are desk-rejected as insufficient for a journal with JAMA's practice-impact standard. The cover letter must explicitly state the anticipated change in clinical practice.

Reporting checklist absent or incomplete for the study design. JAMA requires authors to follow CONSORT for randomized trials, STROBE for observational studies, PRISMA for systematic reviews, and STARD or TRIPOD for diagnostic and prognostic studies, and it asks for the completed checklist with trial and meta-analysis manuscripts. In our pre-submission review work, a missing or incomplete checklist is a common reason for a manuscript to be returned before review.

Word limits exceeded for the article type. JAMA enforces strict word limits by article type: Original Investigation 3,000 words; Brief Report 1,200 words; Research Letter 800 words, with no abstract.

Papers exceeding these limits are returned before peer review, and in our review work the most common cause is body text that has crept into the figure legends or the Methods after a revision; we re-run the body count the way JAMA's instructions define it, excluding the abstract, references, legends, and table content, so the title-page count matches the figure JAMA asks for.

A JAMA submission readiness check evaluates manuscript scope, abstract format, and reporting checklist compliance against these desk-rejection patterns.