5 posts categorized "Abbreviations"

November 21, 2013

Pluralize Numbers and Abbreviations Without Apostrophes


by David Becker

A common mistake people make is to include apostrophes when pluralizing a number or an abbreviation. Apostrophes are generally used in contractions and to indicate the possessive case, but they are not used to form plurals of numbers and abbreviations in APA Style.

For instance, writing “the 1960’s” when referring to that entire decade is incorrect; instead, one should write “the 1960s.” The same rule applies to the plural form of any other type of number, such as describing someone’s age (e.g. “clients in their 80s”), and is discussed further in section 4.38 on page 114 of the Publication Manual.

A similar rule in section 4.29 on page 110 applies to abbreviations. Just as with numbers, don’t include an apostrophe when pluralizing abbreviations. For example, when pluralizing an acronym, such as “CV” for “curriculum vitae,” all you need to do is add an s to the end, as in “CVs.” This rule also applies to standalone letters, as in “The students all received As.” For abbreviations that end with a period, such as “Ed.” to indicate an editor in a reference list entry, add an s before the period, as in “Eds.” When pluralizing an italicized abbreviation, remember not to italicize the s, as in “ps.” Just don’t add an apostrophe.

For more information, take a look at our other posts on punctuation in APA Style. Punctuation is also covered in more detail on pages 87–96 of the Publication Manual. And, of course, please feel free to comment on this post or contact us with any of your style questions.

September 08, 2011

Group Authors

Timothy McAdoo by Timothy McAdoo

In 2010, the estimated number of websites was 255 million. That translates to a staggering number of individual webpages. Who’s writing all those pages? And, how should you cite them in APA Style?

In this post, I’ll focus on just one possibility: group authors.  Although the “who” element for many references is an individual author or authors, “who” can also be a group author. This is often the case for white papers, press releases, and information pages (e.g., “About Us”) on company websites.

For example, the "about" page on the American Psychological Association site (http://www.apa.org/about/) was surely written by one or more real people. But, because no individual byline is listed and because this resides on the organization’s webpage, you would reference it as a group author. That is, the “who” in your reference is a group author.


American Psychological Association. (n.d.). About APA. Retrieved from

Notice that the author portion still ends with a period.

In the reference, spell out the full group author name.  Though you may choose to abbreviate the author name in text, spell it out in the reference list.

In your text, use the author–date format for citations. In this example, the author is “American Psychological Association” and the date is “n.d.”


    According to the American Psychological Association (n.d.), “psychology is a diverse discipline, grounded in science, but with nearly boundless applications in everyday life” (Definition of "Psychology," para. 1).

If you include the citation many times in your paper, you might want to abbreviate the group author name. If so, this introduction should be included with the first use in text:


    According to the American Psychological Association (APA, n.d., Definition of "Psychology," para. 1), “psychology is a diverse discipline, grounded in science, but with nearly boundless applications in everyday life.”

If you decide to abbreviate, do so consistently throughout the paper. Spelling out the name in some sections and abbreviating in others can confuse the reader.

Note that you are not required to abbreviate, even if the group author name appears frequently in your text. The Publication Manual (p. 176) recommends writing out the name of group authors, even if used many times in your text, if the group author name is short or “if the abbreviation would not be readily understandable.”

July 28, 2011

How to Cite the DSM in APA Style

Jeff by Jeff Hume-Pratuch

If you are working in any field that involves human behavior, sooner or later you will need to cite the Diagnostic and Statistical Manual of Mental Disorders (DSM). Published by the American Psychiatric Association (a.k.a. “the other APA”), the DSM provides a set of common criteria and language for talking about dysfunctions of the mind and emotions.

From the beginning, the DSM has been widely used as a guide by state and federal agencies for the reporting of public health statistics and the fulfillment of legislative mandates, as well as its use as a classification guide for research and clinical psychologists.

The DSM has gone through five revisions since it was first published in 1952, and each of those revisions has included substantial changes in structure and definitions. Some of these have been fairly controversial, such as the attempt to remove the term neurosis from DSM-III and the varying treatment of sexual disorders. A new edition (DSM-5) is in preparation, with a projected release date of May 2013, and major changes have been proposed for it as well.

Because of these changes and their effects on areas as disparate as longitudinal research parameters and health insurance benefits, it’s important to be precise when citing the DSM. Below are some guidelines to use in citing the most recent edition.

Citation Examples

American Psychiatric Association. (2000). Diagnostic and statistical 
manual of mental disorders
(4th ed., text rev.). Washington, DC: Author.

If you used the online edition of the DSM, give the DOI in the reference in the publisher position. Individual chapters and other book parts are also assigned DOIs.

American Psychiatric Association. (2000). Diagnostic and statistical
manual of mental disorders
(4th ed., text rev.).
American Psychiatric Association. (2000). Appendix I: Outline for
cultural formulation and glossary of culturebound syndromes. In
Diagnostic and statistical manual of mental disorders (4th ed.,
text rev.). doi:10.1176/appi.books.9780890423349.7060

In text, cite the name of the association and the name of the manual in full at the first mention in the text; thereafter, you may refer to the traditional DSM form (italicized) as follows:

DSM–III (1980) 3rd ed.
DSM–III–R (1987) 3rd ed., revised
DSM–IV (1994) 4th ed.
DSM–IV–TR (2000) 4th ed., text rev.

After you have spelled out the name of the manual on first mention in the text, format the parenthetical citation as follows:

(3rd ed.; DSM–III; American Psychiatric Association, 1980)
(3rd ed., rev.; DSM–III–R; American Psychiatric Association, 1987)
(4th ed.; DSM–IV; American Psychiatric Association, 1994)
(4th ed., text rev.; DSM–IV–TR; American Psychiatric Association, 2000)

What About DSM-5?

The DSM-5 hasn’t been released yet, but there’s been much discussion of the proposed content. If necessary, refer to the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) in text when you cite these discussions. We’ll be back in May 2013 with tips on how to cite the DSM-5 itself, so mark your calendar!

UPDATE: DSM-5 has arrived! Go here for information on how to cite it.

March 31, 2011

How Do You Spell IQ? Abbreviations as Words in APA Style

Timothy McAdoo by Timothy McAdoo

In a recent guest post, Dr. Anthony Onwuegbuzie and colleagues (Onwuegbuzie, Combs, Slate, & Frels, 2010) presented a list of common APA Style errors. “Failure to spell out abbreviations and acronyms as needed” is eighth on the list.

So, what does “as needed” mean? Shouldn’t all abbreviations and acronyms be defined?

Almost, but there are a handful of exceptions. These exceptions are words for which the abbreviated forms have become commonplace. These abbreviations are often better known than their spelled-out counterparts. IQ, for example, is better known than is intelligence quotient. Likewise, your readers are more likely to recognize REM sleep than rapid eye movement sleep.

If these seem arbitrary, don’t worry! You won’t have to phone a friend each time you consider using an abbreviation. Just follow these guidelines, as recommended by the Publication Manual (p. 107):

  • You may use “abbreviations that appear as word entries (i.e., that are not labeled abbr) in Merriam-Webster’s Collegiate Dictionary (2005).” For these few cases, you don’t need to define the abbreviations.
  • Conversely, entries that do include the abbr label are abbreviations that should be defined.
  • If an abbreviation does not appear in the dictionary, you should define it.

Finally, see pages 106108 of the Publication Manual for additional guidance on abbreviations, including how and when to introduce them, examples of under- and overuse, and more.

August 13, 2009

The Flexibility of APA Style


Timothy McAdoo by Timothy McAdoo

Sometimes it’s okay to color outside the lines. Although the stylistic guidelines in the Publication Manual are meant to ensure consistency within scientific writing, we also recognize the importance of a writer’s good judgment. The trick is knowing when it’s okay to do your own thing. It’s even trickier when you know someone may be reading your paper with a red pen in hand!

As an example, let’s consider APA’s guidance on introducing acronyms (from section 4.22): 

Abbreviations introduced on first mention of a term and used fewer than three times thereafter, particularly in a long paper, may be difficult for a reader to remember, and you probably serve the reader best if you write them out each time.

So in your paper on the psychological effects of duckpin versus tenpin bowling, when you mention the American Bowling Congress just twice, spell it out both times (and don’t introduce the abbreviation ABC). 


Clear enough, but note that the Manual says “you probably serve the reader best” by doing this. How, then, should you recognize an exception? Let’s say you are writing a paper on metabolism disorders, and you need to mention very long-chain acyl-coenzyme A dehydrogenase deficiency just two times. Because of the unwieldy nature of this term, wouldn’t it make more sense to introduce the abbreviation (which is VLCADD) in this case? Yep, go ahead: Your readers will thank you!

Still worried about that red pen? If you’ve mastered the fine points of APA Style throughout a manuscript, your choices will be recognized as careful decisions, not oversights. So be sure to display your in-depth knowledge of APA Style in all other areas of your paper: The Publication Manual provides a handy checklist on pp. 241–243.

If you’re still concerned, you might discuss your paper and the APA Style guidelines with your teacher or advisor. You might both still be learning the 6th edition style!

Are there other examples from the Publication Manual where you think flexibility is important? We’d love to hear from you!

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