Abbreviations
Do not use periods within abbreviations, except for U.N., U.S., and Latin-derived abbreviations such as e.g. (“for example”) and i.e. (“that is”). Note that both e.g. and i.e. are always followed by a comma and are not italicized. In text, it is preferable to use “for example” and “that is” rather than the abbreviations.
State names
The names of the 50 U.S. states should be spelled out in text. In lists or tables, the abbreviations may be used. Note that the two-letter all-caps abbreviations are used only in postal addresses.
The names of eight states are never abbreviated in text or lists/tables:
Alaska (AK), Hawaii (HI), Idaho (ID), Iowa (IA), Maine (ME), Ohio (OH), Texas (TX), and Utah (UT).
Below are the abbreviations for the other 42 state names, with postal code abbreviations in parentheses:
| Ala. (AL)
Ariz. (AZ) Ark. (AR) Calif. (CA) Colo. (CO) Conn. (CT) Del. (DE) |
Fla. (FL)
Ga. (GA) Ill. (IL) Ind. (IN) Kan. (KS) Ky. (KY) La. (LA) |
Md. (MD)
Mass. (MA) Mich. (MI) Minn. (MN) Miss. (MS) Mo. (MO) Mont. (MT) |
Neb. (NE)
Nev. (NV) N.H. (NH) N.J. (NJ) N.M. (NM) N.Y. (NY) N.C. (NC) |
N.D. (ND)
Okla. (OK) Ore. (OR) Pa. (PA) R.I. (RI) S.C. (SC) S.D. (SD) |
Tenn. (TN)
Vt. (VT) Va. (VA) Wash. (WA) W.Va. (WV) Wis. (WI) Wyo. (WY) |
Apostrophes
When writing about decades, do not include an apostrophe.
Vaccines were developed for diphtheria, pertussis, and tuberculosis in the 1920s.
Vaccines were developed for diphtheria, pertussis, and tuberculosis in the 1920’s.
Do use an apostrophe when numbers are omitted.
Vaccines were developed for diphtheria, pertussis, and tuberculosis in the ’20s.
Her degree is DrPH ’21.
Note that the apostrophe “faces” left. See the Degrees section under Writing about the School and its people for details about writing degrees.
Apostrophes and pronouns
Personal pronouns do not include apostrophes.
The dog was wagging its tail.
The dog was wagging it’s tail.
Contractions (words with missing letters) do include apostrophes.
The dog is happy because it’s time to play.
The dog is wagging its tail because it’s time to play.
Also, see Commonly confused words: contractions vs. possessives.
Capitalization
In general, most nouns (and other words) in a sentence are not capitalized. If in doubt, err on the side of not capitalizing.
The program was so successful that the ministry of health has since launched its own pilot program based on the model.
The program was so successful that the Ministry of Health has since launched its own pilot program based on the model.
Fields of study are not capitalized.
She is studying public health with a concentration in health policy.
She is studying Public Health with a concentration in Health Policy.
For capitalization of people’s titles, see the Titles section under Writing about the School and its people.
Capitalization after colons
Capitalize the first word after a colon in a sentence if it is a proper noun, starts a complete sentence, or begins a question.
This is what I heard: She is going to leave by noon.
But then I wondered: Where is she going?
Capitalization of headings, headlines, and event titles
School style uses “sentence case” for headings, headlines, and event titles. In sentence case (as opposed to “title case”), only the initial word (and the word following a colon) is capitalized.
Heading – Writing: Maintaining a consistent narrative
Headline – Analysis reveals factors underlying COVID-19 spread in Brazil
Event title – Social Demography Seminar: “Essential and unprotected: Service sector work in a time of COVID-19”
Note: It is helpful if you follow this “sentence case” when submitting an event for the calendar, so all our listings will be consistent.
In other settings, “title case” may be appropriate. In title case, each word has an initial capital letter, unless it is a conjunction (and, or, but) or an article (a, an, the). This means that in title case, even the word “Is” is capitalized. The number of letters in the word is not what matters; what matters is what part of speech it is.
Commas
School style uses the “serial” comma (also referred to as the Oxford comma) before the final “and” or “or” in a sentence to separate elements in a series.
The event included a slide presentation, brief remarks, a question-and-answer period, and a reception.
The reception guests were asked whether they wished to eat chicken, fish, or a vegetarian meal.
In American English, commas go inside quotation marks.
“The reception was quite interesting,” she said.
Use commas around names of states and nations used with city names.
His journey will take him from Dublin, Ireland, to Fargo, North Dakota, and back.
The Selma, Alabama, group saw the governor.
Use a comma with full dates to set off the year.
February 14, 1987, is the target date.
Commonly confused words: contractions vs. possessives
It’s vs. its
“It’s” is a contraction of “It is.” “Its” is a possessive, meaning “belonging to it” or “of it.”
Listen to the wind. It’s so loud! = Listen to the wind. It is so loud!
Listen to the wind. Its so loud!
Its strength is shaking the house. = The strength of it is shaking the house.
It’s strength is shaking the house.
Who’s vs. whose
“Who’s” is a contraction of “who is.” “Whose” is a possessive, meaning “belonging to someone or something previously mentioned” (below, “the child”).
Who’s at the door? = Who is at the door?
Whose at the door?
Is it the child whose name I was just calling? = I was just calling the name of a child; is it that child who is at the door?
Is it the child who’s name I was just calling?
Whose book is this? = Who does this book belong to?
Who’s book is this?
I live in a city whose population is around 500,000.*
*In general, “who” is used only with living things, like people and animals. With inanimate objects and things, like “city,” the word “which” would generally be used. But English does not have the word “whichs,” which would theoretically be the possessive in a construction like this, so “whose” is used.
You’re vs. your
“You’re” is a contraction of “You are.” “Your” is a possessive, meaning “belonging to you/of you.”
You’re reading a very long book. = You are reading a very long book.
Your reading a very long book.
Your book is over 500 pages long. = The book belonging to you is over 500 pages long.
You’re book is over 500 pages long.
Thank you. You’re welcome.
Thank you. Your welcome.
Dashes
Em-dash
The long dash (—) is called an em-dash (so called because it is approximately the width of a capital letter M in the typeface being used). School style is to not put spaces surrounding this dash in text. One of the most common uses of the em-dash is to signal an abrupt change in thought in a sentence.
When the vaccine was finally approved—nearly three months before it was expected—the next step was to begin the nationwide rollout.
On a Mac, the em-dash is made by holding down the option, shift, and minus keys together. On a PC, the em-dash is made by holding down the ALT key and typing 0151 on the number pad.
En-dash
The medium-length dash (–) is called an en-dash (so called because it is approximately the width of a capital letter N in the typeface being used). It is shorter than an em-dash and longer than a hyphen. (Note that AP style does not use en-dashes.) The en-dash has several uses.
It is used to mean “to” or “through,” including with inclusive numbers. Do not put spaces surrounding this dash in text.
Pages 112–187
2–4 pm
When preceded by “from” in text, use the word “to,” not the en-dash:
The event will be held from 9 to 11 am.
The event will be held from 9–11 am.
She was CEO from 1997 to 2006.
She was CEO from 1997–2006.
They were working from Tuesday to Sunday.
They were working from Tuesday–Sunday.
Also use the en-dash to form a compound modifier when one of the words is an open (not hyphenated) compound:
Civil War–era records
global health–related efforts
post–Vietnam War landscape
On a Mac, the en-dash is made by holding down the option and minus keys together. On a PC, the en-dash is made by holding down the ALT key and typing 0150 on the number pad.
Hyphen
The shortest dash (-) is the hyphen. It has several uses.
It is used to connect parts of a compound word or linked words.
The decision-making process was extensive.
She was named the first-ever recipient of the award.
Compound adjectives that precede the noun they modify have hyphens.
On-campus degree format
No hyphen is used when a compound adjective follows the noun it modifies.
Degree format: On campus
Degree format: On-campus
Note that no hyphen is used when the two words do not constitute a compound adjective.
The process of decision making was extensive.
The process of decision-making was extensive.
A hyphen can also indicate a missing or implied element.
It was unclear whether the regulation would bring about a short- or a long-term change.
In low- and middle-income countries, infants exposed to carbon-based fine particulate air pollution had 50 percent higher odds of dying during infancy than babies who were not exposed, according to a new study.
Note the space after the first hyphen, which indicates the missing word. In the examples above, the missing word in the first sentence is “term”; in the second sentence, the missing word is “income.”
And a hyphen is used to indicate a syllable break in words at the end of a line of type.
Hyphens are generally not used in prefixes. See the Prefixes section.
Dates and times
Month, day: Use numerals for days without st, nd, rd or th,
January 23
The months August through February may be abbreviated when used with a date. Do not abbreviate the months March through July.
August 8
Aug. 8
March 16
Mar. 16
Always spell out months with no dates:
October is her favorite month.
Do not separate months and years with a comma:
He left for Bhutan in October 1937.
Set off years with commas when there is a specific date:
The mortgage was paid off April 1, 1998, and they threw a party that night.
Time: Separate time ranges with an en-dash (–), no spaces on either side. Use lowercase am and pm, without periods.
10:00 am–3 pm
10:00 a.m.–3 p.m.
If it’s an exact hour, no “:00″ is required:
12 pm
If a time range is entirely in the morning or evening, use am or pm only once:
6:30–10 pm
If it goes from the morning into the evening (or vice versa), you need both:
“10 am–2 pm”
Italics
Do not italicize Latin-derived words and abbreviations such as “emeritus,” “in vitro,” “e.g.,” and “i.e.” They are in common usage in English.
However, names of genus and species are italicized.
Aedes aegypti mosquitoes
Plasmodium falciparum malaria
AP style does not italicize titles of books, movies, radio and television programs, titles of lectures and speeches, and such. They should instead have quotation marks around them. Note that periods and commas generally go inside quotation marks.
Names of media outlets, such as the New York Times, Boston Globe, CNN, and NPR, are not italicized or set in quotation marks.
Numbers
Words vs. figures
In general, spell out words for the numbers zero through nine. Use figures for 10 and up.
Exception: millions and up and ages (see below).
Another exception: Always use figures for percentages, even for numbers below 10. And in text, generally spell out the word “percent.”
5 percent, 8 percent
five percent, eight percent
Another exception: Spell out numbers if they are the first word in a sentence.
Twenty years ago, she was a graduate student.
20 years ago, she was a graduate student.
Nineteen forty-eight was the year the World Health Organization was established by the United Nations.
1948 was the year the World Health Organization was established by the United Nations.
Mixed forms
Use mixed forms in groups of topically related numbers when some of the numbers are larger than 10 and some are smaller.
The children were lined up in groups of eight, 10, and 12.
Millions and up
Always use figures with millions, billions, trillions.
1 million, 9 billion, 32 million, 2 trillion
Ages
Always use figures with ages, even in mixed groups.
age 1, age 5, age 22
Fractions
Use words for amounts less than one.
one-half, two-thirds
Use fractions for ages.
a child of 2½
Periods
Periods, like commas, go inside quotation marks.
“That was a very interesting class,” she said. He said, “I agree.”
As noted above under Abbreviations, abbreviations do not include periods, except for U.N., U.S., and Latin-derived abbreviations such as e.g. (for example) and i.e. (that is). Note that both e.g. and i.e. are always followed by a comma.
Prefixes
Prefixes are generally not hyphenated.
coeducation, coequal, coexistence, coordinate, cooperate
noncommunicable, nonstandard, noncompliant, nonprofit, nongovernmental, nonnuclear
postdoctoral, postgraduate, postoperative, postbaccalaureate
predate, prearrange, prenatal, preadmission, preelection, preempt, preexisting
reelect, reemerge, reenter, reestablish
subbasement, subspecialty, subphase, substandard
unpolluted, unclassifiable, uncorroborated, unnecessary, unair-conditioned
Exception: Nouns, adjectives, and verbs that indicate occupation or status use a hyphen.
co-author, co-chair, co-host, co-sponsor
Hyphens are also used to distinguish meanings.
unionized (organized into a labor union); un-ionized (a substance that has not formed ions)
recover (regain); re-cover (cover again)
resign (quit); re-sign (sign again)
And hyphens are used when the prefix precedes a word that is capitalized.
un-American, pre-Raphaelite
Punctuation and quotation marks
In American English, periods and commas go inside quotation marks.
“It’s time to go,” she said. “Not yet,” he whined.
“It’s time to go”, she said. “Not yet”, he whined.
She said, “It’s time to go.” He whined, “Not yet.”
She said, “It’s time to go”. He whined, “Not yet”.
So do exclamation points and question marks, if they are part of the original quotation. Note that an additional comma should not appear after the ? or !.
“What time are we going?” she asked. “Not soon enough!” he exclaimed.
“What time are we going?,” she asked. “Not soon enough!,” he exclaimed.
Colons and semicolons do not go inside quotation marks.
He said, “Semicolons seem to freak people out”; I don’t know why that is.
He said, “Semicolons seem to freak people out;” I don’t know why that is.
Semicolons
In general, semicolons are used to indicate a greater separation of thought and information than indicated by a comma but less than that implied by a period.
A call sometime in the evening of Saturday or Sunday would be fine; we have no plans that I know of at this point.
One common use of semicolons is to separate elements of a series when the items are long or when individual segments contain material that requires commas.
People’s health is determined in part by access to social and economic opportunities; the resources and supports available in their homes, neighborhoods, and communities; the quality of their schooling; the safety of their workplaces; the cleanliness of their water, food, and air; and the nature of their social interactions and relationships.
Semicolons go outside quotation marks.
She said, “I was thinking it was time to go”; in fact, it was long past time.
Time
School style uses “am” and “pm” in lowercase and without periods. Note that there should be a space following the time and before the “am” or “pm.” And when both times are either “am” or “pm,” that designation is not repeated.
11:30 am–1:30 pm
11:30am–1:30pm
10–11:30 am
10 am–11:30 am
Titles (general)
Lowercase titles when using them without a name.
the secretary, the president, the senator
In cases where the title is being used in place of the person’s proper name, capitalize the title.
Good morning, Senator.
Titles (academic)
See the Titles section under Writing About the School and Its People for information about School style regarding academic titles.
