When is it appropriate to use abbreviations?

This page reflects guidance from the sixth edition of the Publication Manual.

For the most current guidelines, see the Publication Manual of the American Psychological Association (7th ed.) and our Style and Grammar Guidelines page for the seventh edition.

To maximize clarity, APA prefers that authors use abbreviations sparingly. Although abbreviations are sometimes useful for long, technical terms in scientific writing, communication is usually garbled rather than clarified if, for example, an abbreviation is unfamiliar to the reader.

Some abbreviations may not be in the dictionary but appear frequently in the journal for which you are writing. Although probably well understood by many readers, these abbreviations should still be explained when first used.


  • Minnesota Multiphasic Personality Inventory (MMPI)
  • conditional stimulus (CS)
  • intertrial interval (ITI)
  • consonant–vowel–consonant (CVC)
  • short-term memory (STM)
  • reaction time (RT)

Do not use the abbreviations S, E, or O for subject, experimenter, and observer.

APA Style® does permit the use of abbreviations that appear as word entries (i.e., that are not labeled abbr) in Webster's Collegiate Dictionary. Such abbreviations do not need explanation in text.


  • IQ
  • REM
  • ESP
  • AIDS
  • HIV
  • NADP
  • ACTH

(adapted from the sixth edition of the APA Publication Manual, © 2010)