AMA and ASA Styles Explained: Medicine and Sociology Referencing

The letters are almost the same, but AMA and ASA are different styles for different readers. AMA serves medicine and the health sciences, and ASA serves sociology. If you work in either field, you will probably be asked to use one of them, and it is easy to mix them up.

This guide explains each style in turn, shows examples and compares them side by side. The examples use invented sources to illustrate the format. Always check the edition and any course-specific rules.

AMA style

Where it is used

AMA style is the style of the American Medical Association, used in many medical and biomedical journals and in health science courses. It is a numbered system, in the same family as Vancouver, with its own rules for formatting.

In-text citations

Sources are cited with superscript Arabic numerals, in the order they first appear in the text. The same source keeps its number every time it is cited.

Early mobilization shortens hospital stays.¹

Place the number after the relevant word or phrase. Placement relative to punctuation follows specific rules: numbers usually go outside periods and commas, and inside colons and semicolons. Check the manual or your guide for details.

The reference list

• Title it References.
• Number the entries in the order of first citation.
• Give authors' surnames and initials, with no punctuation between initials: Lee J, Patel R.
• Use italics for journal titles and abbreviate them in standard form.
• Include a DOI where available.

AMA examples

Journal article:

1. Lee J, Patel R. Early mobilization after abdominal surgery. J Clin Nurs. 2021;30(4):512-520. doi:10.0000/example

Book:

2. Gomez M. Fundamentals of Clinical Assessment. 3rd ed. Harbor Press; 2020.

Website:

3. Hand hygiene in health care. World Health Organization. Updated 2021. Accessed March 12, 2025. https://www.example.org/hand-hygiene

Authors in AMA

List all authors if there are six or fewer. If there are more than six, list the first three and add "et al." This is a key point that differs from some other numbered styles, so check which one you are using.

ASA style

Where it is used

ASA style is the style of the American Sociological Association. It is used in sociology and some neighboring social sciences, and is based on the author-date approach of the Chicago Manual of Style, with its own conventions. The current style guide is the 7th edition, published in 2022.

In-text citations

ASA uses the author's last name and the year, with a page number after a colon and no space. There is no comma between the name and the year.

• Parenthetical: Reading skills develop through practice (Patel 2020:45).
• Narrative: Patel (2020:45) argues that reading skills develop through practice.

The reference list

• Title it References.
• Order alphabetically by the first author's last name.
• Place the year right after the author's name.
• Use a hanging indent.
• Give the first author's name with the surname first, and later authors in normal order.

ASA examples

Book:

Patel, Rina. 2020. Reading in the Digital Age. Harbor Press.

Journal article:

Lee, Jordan, and Rina Patel. 2021. "Practice and Comprehension in First-Year Students." Journal of College Learning 14(2):112-29.

Webpage:

World Health Organization. 2021. "Hand Hygiene in Health Care." Retrieved March 12, 2025 (https://www.example.org/hand-hygiene).

The ASA guide gives patterns for many other source types, including reports, theses, interviews and social media. Follow the closest example.

AMA and ASA compared

If you recognize the pattern, you will not confuse them: AMA is a numbered system like Vancouver, and ASA is an author-date system like APA or Harvard.

More source types in each style

Both styles have patterns for sources beyond articles and books. A few examples, with invented details, show the logic.

AMA, chapter in an edited book:

4. Patel R. Pain assessment in older adults. In: Gomez M, ed. Care of the Older Adult. Northfield; 2019:120-145.

AMA, report from an organization:

5. National Institute for Health Research. Falls Prevention Guideline. NIHR; 2022. Accessed March 12, 2025. https://www.example.org/falls

ASA, chapter in an edited book:

Patel, Rina. 2019. "Reading across Class Lines." Pp. 45-67 in Education and Inequality, edited by Marta Gomez. Northfield.

ASA, report:

National Center for Education Research. 2022. Trends in College Reading Skills. Report No. 22-04. Washington, DC: NCER.

ASA, unpublished thesis:

Gomez, Marta. 2019. "Neighborhoods and Schooling." PhD dissertation, Department of Sociology, Northfield University.

If your assignment uses an unusual source, find the closest example in the manual or your library guide.

How to switch between the two

Moving from AMA to ASA, or the reverse, means changing the whole logic of the citations, not just the punctuation. Sources must be re-ordered, since AMA lists by order of citation and ASA lists alphabetically. In-text markers change from superscript numbers to author and year. If you use a reference manager, change the output style before you insert citations, then check each entry, since journal names and the position of the year differ. Do not edit a finished list by hand to convert it. Rebuild it.

Choosing and checking

Your course will normally tell you which one to use. If it does not, ask. Health professions often use AMA or Vancouver, while sociology and many social sciences use ASA or APA. For nursing students, practice differs by program, so check your handbook. A second check on a finished reference list is useful in nursing and health writing, and reference formatting for graduate nursing papers is one way to get it.

A reference manager can output both styles. Check the result carefully: journal abbreviations, author lists and the placement of years are common sources of error. Our citation generator can start an entry, but compare it with a trusted example.

Tables, figures and special formatting

Both styles ask for numbered tables and figures with clear captions, and for credit when you reuse material. In AMA, a table or figure taken from a source carries a numbered citation in its caption or title. In ASA, the caption credits the author and year. If you create a table from published data, cite the data source in a note beneath it. Check your course template for fonts, spacing and heading styles, because AMA journal formatting and ASA paper formatting differ in layout as well as citation.

Common mistakes

• Mixing numbered and author-date formats in one paper.
• Using the wrong edition from an old textbook.
• Alphabetizing an AMA list, which should follow citation order.
• Forgetting the colon before the page number in ASA citations.
• Adding a comma between the author and year in ASA.
• Listing too many or too few authors in AMA.
• Full journal titles in AMA where abbreviations are expected.
• Missing DOIs or access dates for online material.

For another numbered style, see our guide to Vancouver referencing.

A quick checklist

• Do I know which style and edition my course requires?
• For AMA: are superscript numbers in order, and the list numbered the same way?
• For ASA: are citations in (Author Year:page) form, and the list alphabetical?
• Are authors, titles, years, volumes and pages correct?
• Is every source cited in the text listed, and the reverse?

Final thoughts

Despite their similar names, AMA and ASA solve different problems for different fields. Know which one you are using, keep one correct example of each source type on hand and check each entry against it. Then the details become routine, and your references are one less thing to worry about.