Using Serial Commas

by David Becker

This week we address the serial comma, seventh in the list of the Top 10 most common APA Style errors as identified by Onwuegbuzie, Combs, Slate, and Frels (2010).

Also known as the Oxford comma, the serial comma is the final comma in a list of three items or more, and it is used immediately before and, or, and occasionally nor. For example, if Simon & Garfunkel had recorded their classic album Parsley, Sage, Rosemary and Thyme under APA Records, which doesn't actually exist, then that album would have been titled Parsley, Sage, Rosemary, and Thyme with the serial comma included. This rule also applies to parenthetical citations, in which ampersands are used in place of the full word and. For instance, one would say (Lennon, McCartney, Harrison, & Starr, 1964) instead of (Lennon, McCartney, Harrison & Starr, 1964).

There are various aesthetic and technical arguments for why serial commas should or should not be used. Although they aren’t required in journalistic writing, a distinct advantage of using serial commas is clear, unambiguous language, which is a necessity in scientific writing.

As an example of how omitting a serial comma can create ambiguity, if I were to say, "I had lunch with my parents, Barack Obama and the Prime Minister of Australia," it might seem like Barack Obama and the Australian Prime Minister were my parents, which I can personally assure you is not true. On the other hand, if I were to say, "I had lunch with my parents, Barack Obama, and the Prime Minister of Australia," then each of those items is clearly distinct from one another, and Barack Obama and the Australian Prime Minister are no longer my parents, all thanks to the addition of a serial comma.

For more information about commas and their proper usage in APA Style, see pages 88 and 89 of the Publication Manual, Sixth Edition (4.03 Comma). Also, pages 63–65 go into greater detail about creating lists (3.04 Seriation). You may also find it helpful to read two previous APA Style blog entries about creating lists: one on parallelism and another on commas and semicolons.

Lists, Part 6: Overview

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

Lists, Part 5: Bulleted Lists

by 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

Lists, Part 4: Numbered Lists

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

Lists, Part 3: Lowercase Letters

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

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

Lists, Part 2: Commas and Semicolons

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.

Commas

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.

Semicolons

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

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

Lists, Part 1: Parallelism

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.

Parallelism

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

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