32 posts categorized "Punctuation"

June 11, 2010

Formatting Statistics: Using Parentheses

Timothy McAdoo by Timothy McAdoo

The Publication Manual (6th ed.) presents guidelines for formatting statistical and mathematical copy. As noted on page 116 of the Manual, these guidelines reflect "standards of content and form agreed on in the field" and are designed to enhance clear communication.

The most basic guidelines are that statistics should be italicized and shown in parentheses:

In Experiment 1, participants listening to The Smiths were no more likely to dance energetically than were those listening to The Cure (p = .24).

However, when a statistic includes its own parenthetical value (e.g., degrees of freedom that appear with t or F values), you’ll need to separate the statistics from the text with commas. Nested parentheses should be avoided in APA Style.

Consider the next two examples:

In Experiment 2, participants listening to Lady Gaga were more likely to “just dance” than were students listening to The Smiths, t(177) = 3.51, p < .001.

In Experiment 3, participants’ biofeedback indicated a significant impact of listening to up-tempo La Roux melodies, F(1, 144), p < .001, and also a significant impact of listening to melancholy selections from The Decemberists, F(1, 144), p < .001.

Notice how the commas separate the string of statistics from the text, just as they would separate other types of independent clauses.

When you have multiple groups of statistics in a series, use semicolons to separate:

In Experiment 4, an impact was demonstrated for genre, R2 = .31, F(2, 13) = 3.13, p < .001; recording date, R2 = .11, F(2, 13) = 1.53, p < .001; and tempo, R2 = .17, F(2, 13) = 2.33, p < .001.

As a side note, notice that there should be no space between a statistic's symbol and its parenthetical information (in this case the degrees of freedom): that is, F(1, 144) not F (1, 144).

Of course, this just scratches the surface of the potential for reporting statistics. Pages 116–124 of the Manual provide much more detail. What questions do you have? Let us know in the comments.

May 27, 2010

“My Professor Says...”

.rev3 by Jeff Hume-Pratuch  

Dear APA,

My professor says that you can only use a comma in APA Style if there is a rule for it in the book. I told her there are lots of places where you need commas that the book doesn't cover, like after introductory phrases (e.g., “For instance”). She agreed with me but said there was nothing she could do, it's an APA rule. Is this correct?

--Anguished in Austin

Dear Anguished,

Your professor is misinformed. The APA Publication Manual is not intended to be exhaustive in its coverage of grammar and style. Consequently, there are some things outside its purview. If it’s not in the manual, it’s not an APA rule.

Unfortunately, Anguished, we receive letters like yours every day.

“My professor told me my outline had to be in APA Style, but I can’t find any examples of outlines in the manual!”

“My professor said it was against APA Style to use the first person.”

“My professor told me to do a PowerPoint presentation in APA Style. I’ve read the whole book and I can’t find a format for slideshows.”

If your professor’s instructions and the manual seem out of joint, don’t panic! There are several things you can do to ameliorate the situation.

1. Ask your professor to clarify the assignment. Perhaps “do the PowerPoint in APA Style” really means “put the references in your slideshow in APA Style.” And sometimes “APA Style” is just shorthand for “use the author–date system for references, instead of footnotes.”

2. If the professor’s instructions seem to contradict APA Style, ask whether this is intentional. For example, APA Style does not include the use of an outline at the start of a paper, but your professor may have a valid reason for requiring one.

3. Ask the professor if there is a list of specific exceptions to APA Style. The Publication Manual (6th ed.) contains many useful tips for clear and concise writing, but it was written predominantly for scholars seeking publication rather than for students seeking term paper formats. Your department or institution may have its own set of style rules that supersede the Publication Manual in whole or part.

Most problems can be resolved with a modicum of good will on both sides. But if you find yourself really stumped on a point of APA Style, contact APA’s Style Experts (styleexpert@apastyle.org).

Hope this helps!



May 13, 2010

It’s All Latin to Me: Latin Abbreviations in Scholarly Writing

Chelsea blog by Chelsea Lee

The English language loves to appropriate words from other languages and claim them as its own. Some of these words and phrases have become so well used in scientific writing that you can employ them in your writing as abbreviations without any definitions or special attention (for instance, no need for italics). Yet readers new to scientific writing might find themselves scratching their heads and exclaiming, "It’s all Greek to me!" (Though the grammarian in me would point out that all the expressions below actually come from Latin, not Greek.)

The table below focuses on Latin abbreviations common to scholarly writing that may be used without definition in APA Style. Note that this list is not exhaustive. See also section 4.26 (p. 108) of the Publication Manual for more.

Abbreviation Meaning Example use Notes for APA Style
Used inside of parentheses only
cf. “compare” or “consult” (used to provide contrasting or opposing information) Abbott (2010) found supportive results in her memory experiment, unlike those of previous work (cf. Zeller & Williams, 2007). She expands on the working memory literature (see also Evans & Potter, 2005). Never put a comma after. Do not put a period between the c and the f. Use “cf.” to contrast; to compare like things, use “see” or “see also.”
e.g., “for example,” (abbreviation for exempli gratia) Some studies (e.g., Jenkins & Morgan, 2010; Macmillan, 2009) have supported this conclusion. Others—for example, Chang (2004)—disagreed. Always put a comma after.
etc. “and so on” or “and so forth” (abbreviation for et cetera) Students ranked their school subjects (chemistry, math, etc.) in order of preference, first, second, third, and so on, until they had ranked the entire list. A majority ranked science-related subjects (biology etc.) as their second favorite. Put a comma before if used to end a list of at least two other items, as shown in the example.
i.e., “that is,” (abbreviation for id est; used to give specific clarification) The experimenters manipulated the order of presentation (i.e., first, second, or third) of the three images as well their size, that is, whether they were small or large. Always put a comma after.
viz., “namely,” We first replicated our earlier study (viz., Black & Avery, 2008) and then extended it. Always put a comma after.
vs. “versus” The 2 (low vs. high) × 2 (blue vs. green) analysis of variance revealed that the low versus high distinction was not significant. Exception: With legal citations use v. instead (with italics; see also Appendix 7.1, section A7.03, Examples 1–8).
Used inside and outside of parentheses
et al. “and others” Thomas, Greengrass, and Hopkirk (2010) made several excellent points about goal-seeking behavior. Thomas et al. began with how goals are selected. Must refer to at least two people because it is a plural phrase. See section 6.12 (p. 175) for more on how to use.
Never used in APA Style
ibid. abbreviation for ibidem, used in citations to refer again to the last source previously referenced ——— Not used in APA Style; instead give each citation using author names as usual.

Note. All abbreviations in the first section should be used inside of parentheses only, that is, when you are making a parenthetical statement. Outside of parentheses, spell these expressions out using the definitions given in the Meaning column. The abbreviation “et al.” is used both inside and outside of parentheses. Directions on comma use always apply, whether you are abbreviating or not. Although the abbreviation “ibid.” is not used in APA Style, it is included here because it occurs in non-APA scholarly writing and readers may be otherwise unfamiliar with it. Unless otherwise noted, none of these abbreviations should be italicized.

You can download a PDF of the Latin abbreviations table here if you would like to use it as a handout for teaching or classroom purposes.

Feel free to share your contributions in the comments!

March 04, 2010

Lists, Part 6: Overview

Timothy McAdooChelsea by Timothy McAdoo and Chelsea Lee

Earlier in this series, I gave examples of lettered, numbered, and bulleted lists. Whereas those posts provided detail about each type of list and how to construct them, this post synthesizes the information to help you decide what list might be best for your paper.

Chelsea has consolidated this information into a handy table that shows typical uses for each type of list. Please note that it’s a general overview of the APA Style guidelines described in the Manual, not an exhaustive or absolute list. In fact, we’d love to hear other ways you use lists—feel free to leave your suggestions in the comments.

What do you want to do with your series of items? Lettered Numbered Bulleted
Clarify the elements without drawing overmuch attention to the list itself

Visually separate the list from the surrounding text
Show procedural steps
Show a chronology (first, second, third)
Show how items have relative importance (e.g., increasing or decreasing in importance)
Show a general list, with no implied chronology, procedure, order, or differences in importance

You can also download a PDF version of this table here.

What other uses do you find for lettered, numbered, or bulleted lists?

Lists, Part 1  |  Lists, Part 2  |  Lists, Part 3

Lists, Part 4  |  Lists, Part 5  |  Lists, Part 6

March 02, 2010

Lists, Part 5: Bulleted Lists

Timothy McAdooby Timothy McAdoo

This is the fifth in a six-part series about lists. Today I’ll discuss bulleted lists, which are new to APA Style!

Bulleted Lists

As the Publication Manual of the American Psychological Association notes (p. 63), creating a list sometimes “helps the reader understand the organization of key points.” And although numbered lists are useful, in some cases the numbers may imply a chronology or ranking of importance that you don’t intend. Thus, I’m happy to share that bulleted lists are now an official part of APA Style (pp. 64–65)!

Bulleted lists allow a writer to create a list that stands out from the text without the implied chronology or order of importance that a numbered list might convey. Any symbol may be used for the bullets, although small circles or squares are typical software defaults. Here again, when full sentences are used, the first words should be capitalized and appropriate end punctuation should be included.

●  Each child received one plush toy.
●  Some toys were familiar to the children from their experiences in Experiment
    1. In Experiment 1, all children could see but not touch the plush elephant.
    Also in Experiment 1, half of the children could see but not touch the plush
    kangaroo, whereas the other half of the children could both see and touch
    the plush kangaroo.
●  One toy, a plush giraffe, was unique to Experiment 2.

(Note that although we single-space examples in the blog, you should double-space lists in an APA Style manuscript just as you would regular text.)

Bulleted Lists Within Sentences

In the example above, I used full sentences. But, you can also use bulleted lists within a sentence. When you do so, capitalize and punctuate throughout the list just as you would in any sentence. For example, in the following list, note the commas following the first two items, the conjunction “and” included with the second-to-last item, the lowercase used for each item in the list, and the end punctuation with the last item.

Each child was seated at a separate station and given
●  an elephant,
●  a kangaroo, and
●  a giraffe.

And remember that the rule for semicolons when items have internal commas is still applicable:

Each child was seated at a separate station and given
●  an elephant, which all children could see but not touch in Experiment 1;
●  a kangaroo, which half of the children could see but not touch and half of the
    children could both see and touch in Experiment 1; and
●  a giraffe, which was new to all children in this experiment.

A Caveat

Bulleted lists can be effective, but be sure to use them judiciously. Just as with numbered lists, by virtue of their formatting, bulleted lists are likely to draw a reader’s attention away from the running text. Too many bulleted lists in your paper may be visually distracting for a reader. You don’t want each page of your paper to look like a PowerPoint presentation!

There may also be differences in opinion about whether bulleted lists are appropriate for technical articles, dissertations, class assignments, and other types of writing. What do you think? Are you a list maker?

More to Come

In Part 6 of this series, we’ll provide an overview of good uses for each type of list.

Lists, Part 1  |  Lists, Part 2  |  Lists, Part 3

Lists, Part 4  |  Lists, Part 5  |  Lists, Part 6

February 25, 2010

Lists, Part 4: Numbered Lists

Timothy McAdoo by Timothy McAdoo

This is the fourth in a six-part series. Today we’ll look at numbered lists.

Numbered Lists

Numbered lists (as noted on p. 64 of the Publication Manual of the American Psychological Association) can be used to denote items in a series, such as conclusions or procedural steps. By virtue of their formatting, numbered lists stand out from the regular text and are more likely to catch a reader’s attention. So, be sure to use the numbered list format only when the list format will add clarity to the text.

Numbered lists can be useful to show the relationship between items: a chronology of events, each item’s relative importance, and so on.

The items can be single sentences or full paragraphs. In either case, the first words of the sentences are capitalized and appropriate end punctuation should be included.

Each task increased in difficulty.
1. The instructor read the rules, which began on page 2 of the booklet.
    The wording of these rules differed significantly for each group (see
    Appendix A).
2. The instructor asked if there were any questions.
3. After any questions had been answered, the instructor started
    the timer and told the participants to begin.

If the items on the list are not complex and the list itself does not warrant special attention, consider running the items into regular text. See Parts 2 and 3 of this series for more detail on the use of serial commas, semicolons, and lowercase letters.

More to Come

In Part 5 of this series, I’ll cover a list format new to APA Style with the 6th edition: bulleted lists!

Lists, Part 1
  |  Lists, Part 2  |  Lists, Part 3

Lists, Part 4  |  Lists, Part 5  |  Lists, Part 6

February 23, 2010

Lists, Part 3: Lowercase Letters

Timothy McAdoo by Timothy McAdoo

In Part 2, I discussed how to create a simple list with serial commas and when to use semicolons in a list of items with internal commas. Today, I show how lowercase letters may be used as well.

Lowercase Letters

As the Publication Manual of the American Psychological Association states on page 64 (3.04 Seriation), elements in a series may be identified by the use of lowercase letters. Lowercase letters are also useful when you need to clarify a complex list for which the individual elements might otherwise be difficult for a reader to discern.

Each child was seated at a separate station and given one of the following: (a) an elephant, which all children could see but not touch in Experiment 1; (b) a kangaroo, which half of the children could see but not touch and half of the children could both see and touch in Experiment 1; or (c) both the elephant and the kangaroo.

Note that the rule for serial commas or semicolons is still applicable. The lowercase letters simply add an additional visual cue for the reader.

More to Come
In the next two posts of this series, I’ll cover numbered lists and bulleted lists.

Lists, Part 1  |  Lists, Part 2  |  Lists, Part 3

February 18, 2010

Lists, Part 2: Commas and Semicolons

Timothy McAdoo by Timothy McAdoo

This is the second in a six-part series about lists in APA Style. Today I’ll provide examples of serial commas and semicolons.


The most basic type of list appears in the running text of a sentence, with each item separated by a comma. All lists in APA Style should include a serial comma—the final comma before the conjunction.

For example,

Each child was given a plush toy, a building block, and a rubber ball.


This gets more complex when an item or multiple items in your list already have commas. In these cases, separate the items with semicolons:

Each child was seated at a separate station and given the following plush toy or toys: an elephant, which all children saw in the previous experiment; a kangaroo, which only half of the children saw in the previous experiment; or both the elephant and the kangaroo.

In the next example the same principle is applied to a series that includes statistics. Proper and consistent use of commas and semicolons clarifies the grouping of each set of statistics:

The results of Experiment 1 showed a similarity across groups: Group A, t(177) = 3.01, p < .001; Group B, t(173) = 2.31, p < .001; and Group C, t(155) = 3.11, p < .001.

More examples of commas and semicolons within lists can be found in the Publication Manual of the American Psychological Association on pages 63–65 (3.04 Seriation), on page 88 (4.03 Comma), and on pages 89–90 (4.04 Semicolon).

More to Come

In Part 3, we’ll look at how to use lowercase letters to identify elements of a list in APA Style.

Lists, Part 1  |  Lists, Part 2  |  Lists, Part 3

February 16, 2010

Lists, Part 1: Parallelism

Timothy McAdoo by Timothy McAdoo

When I feel overwhelmed with tasks, I often make a list (or two or three).

Because making lists helps me organize my thoughts, I also tend to begin a rough draft of a writing assignment as a series of ideas or bullet points. In most cases, I will expand and expound on these ideas, turning them into complete paragraphs. But, sometimes a list helps clarify an idea as well. As the Publication Manual of the American Psychological Association says, a list “helps the reader understand the organization of key points.”

In the first five parts of this six-part series about lists in APA Style, I will cover three aspects of list style and punctuation:
  • parallelism,
  • serial commas, and
  • semicolons.
And, I’ll detail three types of lists:
  • lettered,
  • numbered, and
  • bulleted.
Finally, in Part 6 I’ll summarize and post a table showing the typical uses for each type of list.


For a general guideline about creating lists, the Manual states that “all items should be syntactically and conceptually parallel” (p. 63). This may seem obvious, but it’s easy to use wording that’s not precisely parallel when first getting your ideas onto paper. On the second draft, assess the structure of your lists carefully.

In this example, I’ve underlined the elements that should be parallel in syntax:

Participants were told to study each picture, to turn the page when the bell rang, and that they should ask about anything unclear in the instructions.

That sentence conveys the meaning, but the lack of parallelism weakens its impact. Consider this alternative:

Participants were told to study each picture carefully, to turn the page when the bell sounded, and to ask about anything they found unclear in the instructions.

And, creating parallelism is not just about making the sentence "sound right." A parallel sentence structure makes it easier for a reader to compare like items and to follow sequences of action, much like a well-structured table makes it easier for a reader to scan and compare entries across rows.

In the following, the writer may think he or she is avoiding redundancy by omitting two instances of “Practice Group”:

Children in Practice Group A and in Groups B and C received no visual stimuli, whereas those in Practice Group D were shown an image of a lion.

But, in technical writing, this type of inconsistency can cause confusion. Was there a substantial difference between a “practice group” and a “group”? Probably not, but it might give your reader pause, especially if both terms are used throughout your paper.

There are many ways you might rewrite this sentence with a parallel structure. Here’s one example:

The researchers provided no visual stimuli to children in Practice Groups A, B, and C, whereas researchers projected an image of a lion for children in Practice Group D.

More examples of parallel structure can be found on pages 84–86 of the Manual.

More to Come

In Part 2, I’ll discuss APA Style guidelines for using commas and semicolons in lists.

Lists, Part 1  |  Lists, Part 2  |  Lists, Part 3

February 04, 2010

Using Brackets in APA Style References

Timothy McAdoo by Timothy McAdoo

This post is part of an ongoing series about how references work. Check out an introduction to the generic APA Style reference and the posts on the author or “who” element, the date or “when” element, the title or “what” element, and the source information or “where” element. An upcoming post will give advice on mixing and matching elements of example references.

Glancing through the references examples on pages 193–215 of the APA Publication Manual, you may notice that some references include information in brackets. These brackets always appear immediately following the title element (and any of its parenthetical information). Understanding this element of an APA Style reference can give you great flexibility when creating references. 

As indicated on page 186, “nonroutine” information can be included in brackets. Fourteen of the most common notations are included on that page (including “Audio podcast,” “Data file,” “Computer software,” and others). But these are not the only possible notations.  Any information that is “important for identification and retrieval” may be included in brackets. 

This is useful when you need to clarify the type of source. For example, although Example 50 (p. 210) shows “[Audio podcast]” after the title element, “[Video podcast]” is another possibility. Likewise, in Example 53 (“Map retrieved online”) brackets are included to clarify that the title element refers to a “[Demographic map].” 

Brackets can also be used to indicate that the title element refers to more than one thing, as in Example 57, where “Eyelink II” refers to both the “[Apparatus and software].” 

In short, if you’re referencing an unusual item, consider using brackets to clarify. 

What’s the most unusual item you’ve ever included in an APA Style reference list?

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