AMA (11/e) Style Guide

The format of authors for in-text citations is different than what is required in the list of references.

In the list of references all authors should be given unless there are more than 6, in which case the names of the first 3 authors are used followed by “et al.

For even more detailed information on the proper use of numerals, see section 18.2 of the AMA Manual.

Numerals (1, 2, 3, etc.) should be used in all writing, except when:

• Use words to express numbers that occur at the beginning of a sentence, title, subtitle, or heading. However, it may be better to reword the sentence so that it does not begin with a number.
  • Example:
    • Okay: Three hundred twenty-eight men and 126 women were included in the study.
    • Better: The study population comprised 328 men and 126 women.
• Common fractions are expressed with hyphenated words.
  • Example: Of those attending, nearly three-fourths were members of the association
• Spell out numbers in quotations or titles of works cited.
• One number may be spelled out, if the sentence requires multiple numbers to be placed next to each other. e.g., "If 12 16-year-olds had this reaction..." should be changed to "If twelve 16-year-olds..."
• When spelling out numerals, hyphenate twenty-one through ninety-nine when these numbers occur alone or as part of a larger number.
• Numbers greater than 100 are spelled out. Also do not use commas or and.
  • Example: one hundred thirty-two

• Measures of time are usually expressed as numerals.
• To indicate a time of day, conventional 12-hour clock time is preferred.  Use AM or PM in smaller typeface but with all capitals. In this typeface style, all the letters take the shape of a capital letter but just smaller. See Example below: 
  • At 5:45 am, October 15, 1994, the researchers completed the final experiment.
•  With 12 o’clock, simply use noon or midnight, whichever is intended. See Example below:
  • ​The 21st century officially began just after midnight on January 1, 2001.

However, 24 hour or military time convention MAY also be used to convey precise timing when needed, such as when describing drug dosage regimens or a 24-hour experiment.

See 18.1.4 of the AMA Manual for further information.

• When dates are provided in the text, use numerals for day and year, and write out the month.

EXAMPLE: April 2, 2010

• If using dates in a table, you may use numerals for the month.

EXAMPLE: 4/2/2010

• But, use the forward slash in dates only in tables and figures to save space (month/day/year). Avoid this presentation of dates in the text.

• Use SI (Le Système International d'Unités) standards for writing measurements. Numbers are always written in plain text, there is a space after the number and prior to the unit, and never a period after the unit (unless it ends a sentence).
• Do not include commas in longer numbers.

EXAMPLE:  1600 km, not 1,600 km.

For more specific information on the correct use of units of measure, see 17.1 in the AMA Manual.

But: When a unit of measure follows a number that begins a sentence, it too must be written out, even if the same unit is abbreviated elsewhere in the same sentence. Rewording the sentence may be preferable (see 17.3, Units of Measure, Format, Style, and Punctuation).

EXAMPLES:

Okay: Two milligrams of haloperidol was administered at 9 pm, followed by 1 mg at 3:30 am.

Better: At 9 pm, 2 mg of haloperidol was administered, followed at 3:30 am by 1 mg.

• BOOKS
  • ​In book titles, capitalize all major words and put in italics.
  • Do not capitalize the, an, a, in, for, or but, unless this word begins the title. Example:
    • Sacks O. Hallucinations. Alfred A Knopf; 2012.
  • In book chapter titles, capitalize only the first word of the title. Example:
    • Boushey CJ. Application of research paradigms to nutrition practice. In: Coulston AM, Boushey CJ, Ferruzzi MG, eds. Nutrition in the Prevention and Treatment of Disease. 3rd ed. Academic Press; 2013:99-105.

• ​​​JOURNALS
  • Journal titles are abbreviated and in italics. 
    • Use PubMed abbreviations for journal titles. See Journals referenced in the NCBI Databases.
    • If no PubMed journal abbreviation exists, use standard abbreviations in the AMA Manual of Style to construct an abbreviated title. 
    • Single word titles, such as Pediatrics, are not abbreviated.
    • Capitalize all major words. 
      • Do not capitalize the, an, a, in, for, or but, unless this word begins the title.
  • In journal article titles, capitalize only the first word of the title. Example:
    • Cannady SB, Rosenthal EL, Knott PD, Fritz M, Wax M. Free tissue transfer for head and neck reconstruction: a contemporary review. JAMA Facial Plast Surg  2014;16(5):367-373.

Do not include “personal communications” in the list of references.  See section, 3.13.10. The following methods may be used in the text:

EXAMPLES:

• In a conversation with H. E. Marman, MD (August 2005).…
• According to a letter from H. E. Marman, MD, in August 2005.…
• Similar findings have been noted by Roberts6 and by H. E. Marman, MD (written communication, August 2005).
• According to the manufacturer (H. R. Smith, oral communication, May 2005), the drug became available in Japan in January 2004.

The author should give the date of the communication and indicate whether it was in oral or written (including email) form. Highest academic degrees should also be given. If the affiliation of the person would better establish the relevance and authority of the citation, it should be included (see the example above, where H. R. Smith is identified as the drug’s manufacturer).

• GENERAL
  • Number references consecutively with arabic numerals in the order in which they are cited in the text.
  • Two references should not be combined under a single reference number.
  • If the citation extends to a second line, do NOT indent (as in APA).
• BOOKS
  • In book titles, capitalize all major words and put in italics.
    • Do not capitalize the, an, a, in, for, or but, unless this word begins the title.
  • In book chapter titles, capitalize only the first word.
• JOURNALS
  • Journal titles are abbreviated and in italics. 
    • Use PubMed abbreviations for journal titles. See Journals referenced in the NCBI Databases.
    • If no PubMed journal abbreviation exists, use standard abbreviations in the AMA Manual of Style to construct an abbreviated title. 
    • Single word titles, such as Pediatrics, are not abbreviated.
    • Capitalize all major words. 
      • Do not capitalize the, an, a, in, for, or but, unless this word begins the title.
  • Title of Journal Article, capitalize only the first word.
  • When citing an online journal, the DOI number is preferred over the URL link.
  • Journal page numbers and dates: 
    • Format is the year followed by a semicolon; the volume number and the issue number (in parentheses) followed by a colon; the initial page number, a hyphen, the final page number followed by a period and are set without spaces.
    • Example:
      Hunter RH, Sykes K, Lowman SG, Duncan R, Satariano WA, Belza B. Environmental and policy change to support healthy aging. J Aging Soc Policy. 2011;23(4):354-371. doi:10.1080/08959420.2011.605642

• See section 3.11 Citing Journal Articles, section 3.12 Citing Books, and the section on Citing Electronic Resources in the AMA Manual for more information and examples.

Use quotation marks to enclose a direct quotation of no more than 4 lines from textual material or speeches.

Brackets are used to indicate your own editorial changes or additions within a quotation.

EXAMPLES:

“Enough questions had arisen [these are not described] to warrant medical consultation.”

Thompson stated, “Because of the patient’s preferences, surgery was absolutely contraindicated [italics added].”

“The following year [1947] was a turning point.”