Choosing a citation style by discipline: a comparison table

If your department or target journal names a style, that overrides everything below. This is what to assume when nobody has told you.

• Medicine, nursing, public health - Vancouver for most journals following ICMJE recommendations; AMA for JAMA-family and US medical-association titles.
• Chemistry, materials, chemical engineering - ACS.
• Law (UK and Commonwealth) - OSCOLA.
• Engineering, computer science, electronics - IEEE.
• Psychology, education, business, social sciences - APA 7, or Chicago author-date in some social science departments.
• Literature, languages, cultural studies - MLA 9.
• History, art history, philosophy - Chicago notes-bibliography.
• UK, Australia, New Zealand, South Africa, Hong Kong, across many disciplines - Harvard, with the caveat below.
• Chinese universities and journals - GB/T 7714 numbered, or the author-year system where a journal specifies it.

Every style above is a variation on one of two mechanisms, and knowing which one you are in explains most of the rules.

Author-date. The citation names the author and year in the text, and the reference list is alphabetical. APA, Harvard, MLA (author-page rather than author-year), Chicago author-date, and GB/T 7714 author-year all work this way. Reordering your argument does not disturb the reference list.

Numbered. The citation is a number, assigned in order of first appearance, and the reference list follows that order rather than the alphabet. Vancouver, AMA, ACS, IEEE and GB/T 7714 numbered work this way. Reordering your argument renumbers everything, which is why citation formatting should be the last thing you do, not the first.

The single most common formatting error is alphabetising a numbered style. It comes from habit, and it is visible at a glance to anyone in the field.

APA is defined by a manual from the American Psychological Association. MLA is defined by the Modern Language Association. OSCOLA is defined by Oxford’s law faculty. Each has one authoritative version you can check against.

Harvard has none. It is an umbrella term for a family of author-date conventions, and individual university libraries publish their own guides, which differ in punctuation, in whether titles take single quotes, and in whether page numbers carry `pp.`

So a Harvard example you find online can differ from the one your tutor handed out with neither being wrong. Before submitting, your institution’s guide is the authority - which is also why our Harvard page names the variant it applies rather than leaving it implicit.

Both number references, both use NLM journal abbreviations, both order by appearance. They are still different styles, and three details give it away.

• In-text marker. AMA uses a superscript number; Vancouver typically uses a number in parentheses or brackets.
• Page ranges. AMA writes them in full - 245-258. Vancouver abbreviates - 245-58. One character, multiplied across every reference.
• Author cutoff past six. Both list every author up to six. Beyond six, AMA keeps the first three plus et al., Vancouver keeps six.

ACS looks similar again but abbreviates journals with periods - Nat. Methods - following CASSI, where the medical NLM convention uses none. If you submit to both medical and chemistry journals, this is the detail that slips.

Whichever style you are in, the order of operations matters. Numbered styles renumber when the argument moves, and any rewriting tool run over a finished reference list can disturb it.

The sequence that avoids rework is: finish the argument, then cut to the word limit, then standardise the citations. Converting the references is the safest of those steps to leave until last, precisely because the body stays frozen while it runs.