When to Use Each Citation Style: APA, MLA, Chicago, Harvard, Vancouver, IEEE, or AMA
There are seven major citation styles supported by this site, and most papers do not need to compare them all — your discipline picks the style for you in most cases. But the cases where it does not, or where the rules are not obvious, are where students lose hours to picking the wrong style and reformatting. This guide maps disciplines to styles, covers the interdisciplinary cases, and explains how to handle the situations where the choice is genuinely open.
The shortest answer: APA for social sciences and health, MLA for literature and humanities, Chicago notes–bibliography for history and art history, Chicago author–date for sciences using Chicago, Harvard for UK universities and business, Vancouver for biomedical, IEEE for engineering, AMA for U.S. clinical medicine.
The three things that pick a style for you
In order of priority:
Your assignment. If the assignment specifies a style — and most do — that is your answer. The instructor or department has thought about which style fits the work and the discipline; matching the specified style is part of what you are being graded on.
The journal or venue. If you are submitting for publication, the journal’s instructions for authors are the authoritative source. Most journals specify a style, often with small house modifications (a custom heading format, a particular DOI rendering, specific page-number conventions). Submit in the journal’s style; reformat for production after acceptance.
Your discipline’s convention. When neither the assignment nor a target venue specifies, fall back to your discipline’s default. The convention is not arbitrary — it reflects how readers in the field expect to encounter citations, and it makes your work legible to those readers without friction.
The discipline-to-style map
The styles arrange themselves along two axes: how citations appear in the text (author–date, author–page, or numeric), and which fields have adopted each. The table below summarizes the disciplinary defaults; the per-style guides cover the mechanics.
| Discipline | Default style | Why |
|---|---|---|
| Psychology | APA 7 | APA is the American Psychological Association’s own style — adopted across the field since the 1950s. |
| Education | APA 7 | Aligns with the social-science conventions and the journals education research publishes in. |
| Nursing | APA 7 | Most nursing journals follow APA; some shift to AMA for clinical research. |
| Sociology | APA 7 or Chicago author–date | Discipline-internal mix — American Sociological Review uses ASA style (Chicago-like); most other sociology journals use APA. |
| Political science | APA 7, Chicago author–date | Depends on the subfield — comparative politics often uses Chicago; international relations often uses APA. |
| Economics | Chicago author–date | Most economics journals use Chicago author–date; some use APA. |
| Literature | MLA 9 | MLA is the Modern Language Association’s own style — the default in English and comparative-literature departments. |
| Languages and linguistics | MLA 9 | MLA is the default; linguistics journals often use LSA style for technical writing. |
| Film studies | MLA 9 | MLA’s container model handles film as a source type cleanly. |
| Composition and rhetoric | MLA 9 | Most first-year composition courses use MLA. |
| History | Chicago notes–bibliography | Footnotes carry discursive citation material that fits humanities writing patterns. |
| Art history | Chicago notes–bibliography | Same rationale — footnotes for the long citations that art history requires (catalog entries, exhibition references). |
| Religion and theology | Chicago notes–bibliography | SBL (Society of Biblical Literature) Handbook extends Chicago for biblical-studies-specific cases. |
| Philosophy | Chicago notes–bibliography | Many philosophy journals use Chicago; some use a variant of MLA. |
| Business / management (UK) | Harvard (Cite Them Right) | Standard in UK business schools and most UK universities. |
| Business / management (US) | APA 7 | American business schools generally follow APA. |
| Engineering | IEEE | IEEE is the Institute of Electrical and Electronics Engineers’ own style; the default for engineering papers and IEEE journal submissions. |
| Computer science | IEEE or ACM | IEEE for most journal submissions; ACM has its own style for ACM-published venues. |
| Medicine (clinical, US) | AMA 11 | AMA is the American Medical Association’s own style; default for JAMA-family journals. |
| Medicine (biomedical, international) | Vancouver | Vancouver follows the ICMJE recommendations and is the default for biomedical journals internationally. |
| Public health | AMA 11 or APA 7 | AMA for clinical journals; APA for behavioral and policy work. |
| Geography | Harvard or APA 7 | UK geography uses Harvard; American physical geography often uses APA. |
| Law (US) | Bluebook (not covered) | Specialized legal-citation system; outside the seven major styles. |
| Law (UK) | OSCOLA (not covered) | Oxford Standard for Citation of Legal Authorities; outside the seven major styles. |
The strong signal in this table is that most disciplines have a clear default — and that the default reflects the field’s writing conventions rather than an aesthetic choice. Where the table shows two styles, the secondary one is usually the right answer when the primary style is unfamiliar to the writer or when a specific journal prescribes otherwise.
When the assignment leaves it open
Some assignments — particularly undergraduate research papers and capstone projects — leave the style choice to the student. Three heuristics produce a reasonable default.
Match the journals you are citing most. Your reference list will be cleaner if the style you use matches the style of the work you cite. APA cites APA-formatted journals cleanly; MLA cites MLA-formatted humanities sources cleanly. The friction comes from citing many APA-formatted sources in MLA — every entry requires manual reformatting from how the source itself presents.
Match your degree program’s other writing. If every other paper in your major was in APA, sticking with APA is the path of least resistance. Graders reading dozens of papers in one style will notice an outlier; some will count it against you, others will not, but switching styles when you do not have to is friction you do not need.
Pick MLA for general humanities, APA for general social-science or scientific writing. When the question is genuinely open and neither of the heuristics above applies, MLA is the safe humanities default and APA is the safe everything-else default. Both are widely recognized; both have extensive student-facing documentation; both are supported by every citation tool.
Interdisciplinary work and edge cases
Cross-disciplinary papers. A psychology paper that draws on history of science still cites in APA, because psychology is its home discipline. A literature paper that uses sociological methods still cites in MLA. The home discipline’s convention wins because that is who will grade or peer-review the work. If two disciplines have equal claim — a digital humanities paper that splits between literature and computer science — pick one based on where the paper will be submitted and apply it consistently throughout.
Theses and dissertations. Most programs publish a thesis manual that specifies the style. The manual usually adopts one of the seven major styles with small modifications (a custom title-page format, specific spacing rules, sometimes a custom heading hierarchy). Follow the manual exactly — thesis examiners check formatting closely because the document is meant to be archival.
Multi-author papers. When co-authors come from different disciplines and prefer different styles, the choice usually defaults to the discipline that owns the journal or venue you are targeting. If you are submitting to a psychology journal, use APA regardless of where the co-authors come from.
Conference papers vs journal papers. A conference paper sometimes uses the conference’s house style (often IEEE for engineering, ACM for computer science); the corresponding journal version may need to be reformatted to the target journal’s style. Save the source-data extraction once; reformat the output as venues change.
Switching styles after you have started
If you discover partway through a paper that you should have used a different style, the switch is mechanical but not free.
Generator-produced citations can usually be regenerated in the new style by selecting the new style in your tool and re-running the references. This site’s generator changes output by selecting the style; the work is the time required to re-paste each entry.
In-text citations require manual conversion. Every (Chen, 2021) becomes (Chen 2021) or (Chen 47) depending on the target style. A search-and-replace pass catches most of them; a careful read-through catches the rest.
The heading and the back-matter format need updating: “Works Cited” to “References” or “Bibliography,” bolded to not-bolded (APA versus MLA/Chicago), alphabetization order if you are switching from a numeric style to an author–date style or vice versa.
The cost of switching is high enough that picking the right style at the start is worth ten minutes of checking the assignment, the journal, and the discipline. The cost of not switching, when the wrong style has been used throughout, is usually higher.