英语语法：126 Formatting Vertical Lists（在线收听）

Grammar Girl here.

Today's topic is how to format vertical lists.

Most of the grammar books I own only partially address vertical lists. One book discusses capitalization, another partially discusses punctuation, and so on. Only the Chicago Manual of Style gives the topic the respect it deserves and even there the information is spread out in different sections.

Experts have raised valid concerns that people overuse lists in PowerPoint presentations (1) and for presenting complex information (2),  but the scant attention to lists in most style guides has always baffled me because you can hardly open a web page, marketing brochure, or user manual without walking smack into a list. Marketing experts and web designers know that most people visually scan these kinds of simple or instructional documents instead of reading every word, and that lists improve a scanner's ability to remember key points (3, 4).

Bullets, Numbers, and Letters
If you're going to use a list, the first question to ask yourself is what kind of list you should use.

Bullets are just big dots, and you use them to make a bulleted list when the order of the items doesn't matter. For example, you could use bullets to list the items you want everyone to bring to a beach party. I wish I were in Santa Cruz right now. I'd have a party and make s'mores. Everyone would need

Chocolate bars
Graham crackers
Marshmallows
Pointy sticks

When the order isn't important, I usually list the items alphabetically or in some other way that seems to make sense. The list in the s'mores example is alphabetical, but if I called the pointy sticks something that didn't fall at the end alphabetically, I still would have grouped all the food items together and put sticks at the end. In marketing materials, you probably want to put your most important product feature or selling point first.

Numbers are reserved for instances where the items in the list need to follow a specific sequence. You could use numbers to list the step-wise tasks that are required—in order—to start up a piece of machinery, for example. To turn on my laptop

1. Open the cover
2. Push the start button
3. Make tea while the applications load

Finally, letters are useful when you're implying that readers need to choose individual items or when items don't need to follow a specific sequence, but you want to refer back to an item later. For example, GoToMyPC is a neat product:

a. Set up takes just minutes
b. Internet access is all you need to access your computer
c. They're offering a 30-day free trial

Letters make sense with that list because the order doesn't matter, and I'll refer back to item (c), the free trial, at the end of the show. You can use either capital or lowercase letters for your list. Most of the examples I've seen use lowercase letters, but I haven't been able to find a source that discusses the reasoning for choosing one or the other. Again, just make sure you are consistent.

Introductory Colons
After you've decided what kind of list to use, the next decision you're going to face is how to punctuate the statement that comes right before your list. Should you use a colon? A comma? Nothing?

If your lead-in statement is a complete sentence, then you can use a colon at the end to introduce your list.

On the other hand, if your lead-in statement is a sentence fragment, don't use a colon. It's fine to lead into a list with a sentence fragment, but most of the time, following the sentence fragment with a colon is wrong. Although there are  instances where it is acceptable (see note 1, below), they are rare and the colon is never mandatory. So, the easiest and safest thing to do is avoid putting colons after sentence fragments altogether.

A firm rule is never to put a colon after a verb in a statement that leads into a list. For example, the phrases my favorite things are and everyone should bring are sentence fragments, and should not be followed by a colon. In fact, don't put any punctuation after this kind of statement; you wouldn't put a punctuation mark there if it were just part of a regular sentence, so you don't need anything there if it is leading into a list (see note 2, below).

Capitalization
After you've completed the introductory sentence, your next question will be whether to capitalize the first letter in the statements that come after your bullets, numbers, or letters.

If your list item is a complete sentence, capitalize the first letter. If your list item isn't a complete sentence, you can choose whether or not to capitalize the first letter—it's a style issue. The only thing that is important is to be consistent. I capitalize the first letter of everything in lists because it's easier to remember “capitalize everything” than it is to remember “capitalize complete sentences and use lowercase for sentence fragments.”

Punctuation
With capitalization covered, you're on to your items, and at the end of the first one you have to decide what kind of punctuation to use.

If your list items are complete sentences, or if at least one list item is a fragment that is immediately followed by a complete sentence, use normal terminal punctuation: a period, question mark, or exclamation point.

Web Bonus: Example

For the following reasons, I feel bad for people who don't visit the web site:

They will miss this web bonus.They can't sign up for the e-mail newsletter with free grammar tips.
They missed the fun cartoon last week.

If people came to the web site, they could

See the web bonus. It's an extra learning tool that was too long to put in the podcast.Sign up for the newsletter. It comes by e-mail every week or two and has a free grammar tip, links to all the transcripts for the week, and network news.
See the cartoons. Cartoons are wonderful memory tools.

If your list items are single words or sentence fragments, you can choose whether to use terminal punctuation. Again, what's important is to be consistent. I don't use terminal punctuation after single words or sentence fragments. I think periods look really strange after things that aren't sentences.

Finally, don't put commas or semicolons after the items, and don't put a conjunction such as and  before the last item (see note 3, below).

Parallelism
OK, now that you've got the mechanics down for lists, don't forget to be a good writer and make sure that all of your list items are parallel. That means each list item should be structured the same way. They should all be fragments or they should all be complete sentences. If you start one bullet point with a verb, then start every bullet point with a verb. Here's an example of a list that uses parallel construction:

For Aardvark, a vacation involves

Attending lecturesReading books
Seeing sights

Each bullet point is formed the same way.

On the other hand, even though the following list is grammatically correct, it's considered poor writing because the list items aren't parallel.

For Aardvark, a vacation involves

Attending lecturesBooks
Many trips to famous destinations

Again, that's an example of bad writing because the list items aren't parallel.

Notes

Much of This Comes Down to Style
A final note: Many of the points I've covered are style issues, meaning that I've run across multiple books and online style guides that make different recommendations. My recommendations are based on my assessment after checking about 20 different grammar handbooks and style guides and on what seems logical to me. For example, I didn't find any source that discussed how to order items in a bulleted list, so I made up the recommendation to write them alphabetically because it seems to be the best solution. However, if your organization has a designated style guide, be sure to check it to see if your house style differs from any of my recommendations.
That's all.