APA vs MLA vs Chicago: which citation style should you use?

Every field cites its sources, but not in the same way. A psychology paper says (Rivera & Chen, 2021), a literature essay says (Rivera 112), and a medical journal prints a small superscript number. This guide explains how the major citation styles work, which disciplines use them, and how to choose.

The short answer

Use the style you are told to use. Journals state their style in their author guidelines, and departments and instructors usually name one for theses and coursework. Only when nobody specifies should you choose, and then the safest choice is the style most common in your field.

Three ways to cite

Almost every style belongs to one of three families:

• Author-date: the text names the author and year, and the reference list is alphabetical. APA, Chicago author-date and Harvard work this way.
• Numbered: the text carries a number, and the reference list is in the order sources are first cited. Vancouver, IEEE, AMA and Nature work this way.
• Notes: the text carries a footnote or endnote number, and the note holds the citation. Chicago notes and bibliography works this way.

MLA sits close to the author-date family but uses the author and page number instead of the year. The examples below all cite the same invented study, so you can compare them directly.

APA (7th edition)

APA is the standard in psychology and widely used in education, nursing, business and the social sciences. In-text citations give the author and year: (Rivera & Chen, 2021), or Rivera and Chen (2021) when the names are part of your sentence. With three or more authors, cite only the first followed by "et al."

The reference list is titled References, alphabetical by first author, with a hanging indent. A journal article looks like this, with the journal name and volume in italics: Rivera, L., & Chen, D. (2021). Short sleep and next-day working memory in college students. Journal of Student Health, 14(2), 101-115. Article titles use sentence case, and a DOI, when there is one, goes at the end as a link.

MLA (9th edition)

MLA is the standard in literature, languages and much of the humanities, where readers often need to find a quoted passage. In-text citations give the author and page: (Rivera and Chen 112). The list at the end is titled Works Cited.

MLA builds each entry from a set of core elements in a fixed order: author, title of source, title of container, other contributors, version, number, publisher, publication date and location. The same article in MLA: Rivera, Luis, and David Chen. "Short Sleep and Next-Day Working Memory in College Students." Journal of Student Health, vol. 14, no. 2, 2021, pp. 101-15. Titles use title case, and article titles go in quotation marks.

Chicago (18th edition)

The Chicago Manual of Style offers two systems, and you choose one:

• Notes and bibliography, used across history, the arts and many humanities fields. A superscript number in the text leads to a footnote or endnote with the full citation; later citations of the same source use a shortened note. A bibliography at the end lists every source.
• Author-date, used in the sciences and social sciences. It works much like APA: (Rivera and Chen 2021, 112) in the text and a reference list at the end.

Chicago is also the style many publishers use for books, which is why editors often know it best.

Vancouver

Vancouver is the numbered style used across medicine and the biomedical sciences. Sources are numbered in the order they are first cited, and the same number is reused each time that source appears. Journals differ in how they show the number: in square brackets, in parentheses or as superscript. The reference list follows the numbers and abbreviates journal titles: Rivera L, Chen D. Short sleep and next-day working memory in college students. J Stud Health. 2021;14(2):101-15.

Vancouver grew out of the uniform requirements agreed by medical journal editors, and the U.S. National Library of Medicine's Citing Medicine is its detailed reference. Many journals publish their own variant, so check the author guidelines.

IEEE, AMA and Nature

• IEEE is the numbered style of engineering, computer science and electronics. Citations appear in square brackets, like [1], and the reference list is in citation order.
• AMA (11th edition) is common in medical journals. It numbers sources in citation order and shows the numbers as superscript.
• Nature and many other journals use their own house styles, usually numbered superscripts. The author guidelines are the authority.

Harvard

Harvard is a family of author-date styles common in the UK and Australia. There is no single official version: each university publishes its own guide, and details such as punctuation and the placement of the year differ between them. If your institution says Harvard, use its guide rather than a generic one.

Which style for which field

• Psychology, education, nursing and the social sciences: APA.
• Literature, languages and cultural studies: MLA.
• History and the arts: Chicago notes and bibliography.
• Medicine and the biomedical sciences: Vancouver or AMA, as the journal requires.
• Engineering and computer science: IEEE.
• UK and Australian coursework: your university's Harvard guide.

Tips that save hours

• Let software format the citations. Typing them by hand invites small inconsistencies that reviewers notice.
• Keep the DOI or PubMed ID of every source. It is the most reliable way to recover full, correct details later.
• Check the reference list against the text before you submit: every in-text citation needs an entry, and every entry needs a citation.
• If you might switch journals, keep citations as live fields rather than plain text, so changing style is a click, not a weekend.

Good citation starts long before formatting, with a well-kept library. How to organize research papers covers that, and How to write a literature review covers where citations do their heaviest work.

Citing from Mosaic

The Mosaic add-ins for Word and Google Docs search your project library from a panel beside your draft, insert citations as you write and build the bibliography in APA, MLA, Chicago, Harvard, Vancouver, IEEE, AMA or Nature style. See integrations for where to get them.