APA: Abbreviations

• Avoid abbreviations (acronyms) except for long, familiar terms (MMPI).
  

• Explain what an abbreviation means the first time it occurs: American Psychological Association (APA).
  

• If an abbreviation is commonly used as a word, it does not require explanation (IQ, LSD, REM, ESP).
  

• Do not use the old abbreviations for subject, experimenter, and observer (S, E, O).
  

• The following abbreviations should NOT be used outside parenthetical comments:
  

cf. [use compare]
e.g. [use for example]
etc. [use and so forth]
i.e. [use that is]
viz. [use namely]
vs. [use versus]

• Use periods when making an abbreviation within a reference (Vol. 3, p. 6, 2nd ed.)
  

• Do not use periods within degree titles and organization titles (PhD, APA).
  

• Do not use periods within measurements (lb, ft, s) except inches (in.).
  

• Use s for second, m for meter.
  

• To form plurals of abbreviations, add s alone, without apostrophe (PhDs, IQs, vols., Eds).
  

• In using standard abbreviations for measurements, like m for meter, do not add an s to make it plural (100 seconds is 100 s); when referring to several pages in a reference or citation, use the abbreviation pp. (with a period after it and a space after the period).
  

• Do not use the abbreviation "pp." for magazine or journal citations; just give the numbers themselves. Do use "pp." for citations of encyclopedia entries, multi-page newspaper articles, chapters or articles in edited books.
  

• Use two-letter postal codes for U.S. state names (GA).