Vancouver vs AMA Referencing: Which Style to Use

Vancouver and AMA are both numbered styles built on the same NLM foundations. The differences are small, but editors and copyeditors notice every one of them.

Explainer · 8 min read · Directive Publications Editorial Team

The short answer: the journal decides

If you are choosing between Vancouver and AMA referencing for a manuscript, the decision is already made for you. Open the target journal's instructions for authors, find the references section, and use the style it names and the examples it shows.

That is not a dodge. Both styles are standard in medicine, neither is more correct, and editors do not reward one over the other. What they notice is a reference list that ignores the journal's own rules, because it signals that the manuscript was prepared for somewhere else.

The useful question is a different one: what actually changes when you move between the two, so you can check a reference list quickly and fix it without starting over? That is what this explainer covers.

Where the two styles come from

Vancouver style takes its name from a 1978 meeting. A small group of general medical journal editors met informally in Vancouver, British Columbia, to agree a common format for manuscripts. The group became known as the Vancouver Group, and its requirements, including reference formats developed by the US National Library of Medicine (NLM), were first published in 1979. The group grew into the International Committee of Medical Journal Editors (ICMJE).

Today the rules live in the ICMJE Recommendations. The ICMJE guidance on preparing a manuscript says references should be numbered consecutively in the order in which they are first mentioned in the text, identified by Arabic numerals in parentheses, and formatted according to NLM's sample references and Citing Medicine, 2nd edition. Journal titles are abbreviated in the style used for MEDLINE. When a journal says "Vancouver", "NLM style" or "ICMJE style", it means this family.

AMA style is defined by the AMA Manual of Style: A Guide for Authors and Editors, now in its 11th edition, published in 2020 by Oxford University Press and maintained online with published updates. It is the style JAMA itself uses. JAMA's instructions for authors tell authors to number references in the order they appear in the text, identify them with superscript arabic numerals, follow AMA style and abbreviate journal names according to the journals list in PubMed.

Both are citation-sequence styles. Neither is an author-date style like APA or Harvard. So switching between them changes details, not structure.

What the two styles share

Before looking at differences, it helps to know what you will not need to change:

• Numbering. Sources are numbered in the order they are first cited, and a source keeps its number every time you cite it again.
• Reference list order. The list runs in numerical order, not alphabetically.
• Author names. Surname followed by initials, with no full stops between the initials and commas between authors.
• Article titles. Written in sentence case, so only the first word, proper nouns and abbreviations are capitalised.
• Journal abbreviations. Both use the NLM abbreviation, such as N Engl J Med, which you can look up in the NLM Catalog.

If your reference list already gets these right, converting it from one style to the other is a short job.

The differences that matter

These are the details that change between the two styles for a standard journal article. The Vancouver column follows the ICMJE guidance and NLM's sample references; the AMA column follows the 11th edition as JAMA applies it.

Two points need a caveat. First, Citing Medicine itself lists all authors as NLM practice and treats limiting the list, for example to the first three or first six followed by et al., as an acceptable option when space matters. The six-author rule comes from NLM's sample references page, which ICMJE points authors to. Second, the in-text format for Vancouver varies more than any other detail. Parentheses, square brackets and superscripts all appear in journals that describe their style as Vancouver, so follow the journal's examples.

One article in both styles

Here is the same randomised trial, published in the New England Journal of Medicine in 2019 with seven authors, formatted both ways.

Vancouver (following NLM's sample references):

Dodick DW, Lipton RB, Ailani J, Lu K, Finnegan M, Trugman JM, et al. Ubrogepant for the treatment of migraine. N Engl J Med. 2019 Dec 5;381(23):2230-41. doi: 10.1056/NEJMoa1813049.

AMA (11th edition):

Dodick DW, Lipton RB, Ailani J, et al. Ubrogepant for the treatment of migraine. N Engl J Med. 2019;381(23):2230-2241. doi:10.1056/NEJMoa1813049

Read them side by side and five changes stand out:

1. Vancouver names six authors before et al.; AMA names three.
2. AMA sets the journal abbreviation in italics.
3. Vancouver includes the publication month and day; AMA gives only the year.
4. Vancouver shortens the page range to 2230-41; AMA keeps 2230-2241.
5. The DOI is written differently, and only Vancouver ends it with a full stop.

The in-text citations differ too. A sentence in AMA style ends with a superscript after the full stop, like this.¹ A journal applying the ICMJE wording literally would instead place the number in parentheses, like this (1).

How to decide which style to use

Work through these situations in order:

1. The journal names a style. Use it, and follow the journal's own examples where they differ from a general guide. A journal's examples are the version its copyeditors will check against.
2. The journal says "Vancouver" without examples. Use the ICMJE wording and NLM's sample references as your baseline, and look at a recent article in the journal to see how it handles in-text numbers and author lists.
3. The journal names AMA style or the AMA Manual of Style. Use AMA 11th edition rules, including the three-author et al. rule and italic journal abbreviations.
4. You have no target journal yet. Do not format by hand. Keep your references in a reference manager and apply the style once the journal is chosen.
5. You are moving a rejected paper to a new journal. Reformat the references as part of the resubmission. If the move happens through a manuscript transfer between journals, check whether the receiving journal asks for its own format before review or only after acceptance.

For a thesis or dissertation, the institution's rules usually apply rather than a journal's. Ask your graduate school or supervisor which style they expect before you build the reference list.

Mistakes worth checking before you submit

Most reference problems are not about style at all. They are about accuracy, and both styles assume your references are correct.

1. Every reference matches the cited source. JAMA's instructions state that authors are responsible for the accuracy and completeness of their references, and that AI tools and chatbots should not be used to generate or format references; standard reference managers may be used instead.
2. No retracted articles cited as if valid. The ICMJE guidance asks authors not to cite retracted work except when discussing the retraction, and names PubMed as the authoritative source for retractions in MEDLINE-indexed journals.
3. Personal communications handled correctly. ICMJE advises against citing them unless the information is essential and not available publicly, and then in parentheses in the text with the person's name and the date, not as a numbered reference.
4. Journal abbreviations come from NLM, not from memory or from the journal's own website banner.
5. Reference manager output checked by eye. Styles can differ on author cut-offs, and imported records sometimes carry wrong page numbers, missing issues or title-case titles.
6. Datasets and software cited properly. Both styles can cite them; our guide to citing data, software and code covers what to include.

Reference formatting is one of many small checks that slow a first submission down. The manuscript submission checklist puts it in context with the rest.

The practical takeaway

Learn the shared structure once: citation-order numbers, NLM journal abbreviations, sentence-case titles and surname-plus-initials authors. Then treat Vancouver and AMA as two settings of the same tool. The settings that change are the in-text number, the author cut-off, italics, the date, the page range and the DOI.

Keep your library in a reference manager, choose the journal first, apply its style last, and check the result against the journal's own examples before you submit. That order saves you from formatting the same list twice.

Directive Publications sets out its requirements for manuscripts in its author guidelines. Read them before you format, and when your manuscript is ready you can submit it directly.