Grammar and Punctuation

Action verbs

Action verbs are short and direct. Avoid using the noun form when using the verb is simpler and clearer. Use does verbs instead of is verbs. Example: He runs instead of He is running.

Incorrect: give consideration to / is applicable to
Correct: consider / applies

Active voice

Use active voice whenever possible and appropriate. In the active voice, the subject of the sentence acts. In the passive voice, the subject of the sentence is acted upon. Verbs in the active voice are stronger, enhance clarity, and make a sentence easier to read. Passive voice is appropriate when the actor is unknown, unimportant, or obvious, e.g., small items are often stolen.

Passive: The decision has been changed.
Active: NIH changed the decision.


AP Stylebook: Apostrophes

Apostrophes are used in contractions and with possessive nouns, but never to denote plural.

In contractions, the apostrophe stands for omitted letters or numbers.


We’re working on a cure.
The disease first appeared in the ’80s.

The possessive case denotes ownership or possession, and the apostrophe replaces the word of (children’s health stands for the health of children).


the vaccine’s availability (singular noun)
the virus’ potency (singular noun ending with an s)
the agencies’ policies (plural noun ending with an s)
women’s health issues (plural noun not ending with an s)
the meeting informed Congress’ decision (proper noun ending with an s)

Never use 's to form the plural of an abbreviation or number.

Incorrect: We will issue many RFP’s this year.
Correct: We will issue many RFPs this year.

Incorrect: The disease was eradicated in the 1970’s.
Correct: The disease was eradicated in the 1970s.

Avoid unnecessary words

Below are some frequently used unnecessary words and phrases and their alternatives.

Instead of: Use:
Utilize use
Due to the fact that because
In the event that if
Prior to before
As a result of because
For the purposes of to
In order to to
Reason why reason
Whether or not whether
At the present time now, currently
Has the ability to can
Is able to can
As well as and
Period of time time, period

Eliminate most intensifying modifiers, such as very.

Comma, serial comma

AP Stylebook: Comma

AP style omits the serial comma (the comma before the “and” in a list), so do not include the serial comma for press releases. For other NIH web writing or publications, the serial comma is acceptable and can be clarifying.

Example: “ACTIV has launched hundreds of research studies on diagnosis, prevention, and treatment strategies.”

Continuous, continual

Continuous occurs without interruption, while continual occurs at regular intervals.


AP Stylebook: Dashes

Em dash

Em dashes (—) can be used in pairs to mark off additional information that is not essential to understand the sentence. Here they function similarly to parentheses or a pair of commas. An em dash is usually written without spaces on either side, but AP style calls for a space on both sides. With or without spaces is acceptable for NIH web writing.

Example: Dark leafy greens — such as spinach, kale, and chard — are an important part of a healthy diet.

En dash

Use an en dash (–) without spaces on either side to show ranges in numbers and dates and to express equivalency between two functions in compound terms like clinician–scientist. AP does not use en dashes, but they are acceptable for NIH web writing.

Example: The bubonic plague pandemic lasted from 1346–1353.


AP Stylebook: Ellipsis

Geographic terms

AP Stylebook: Geographic Names


AP Stylebook: Hyphen
Use a hyphen between two words that form a compound modifier when that modifier immediately precedes the noun it modifies. When a compound follows the noun it modifies, hyphenation is usually unnecessary. Compare:

  • Applications undergo a rigorous two-stage review.
  • The applications are reviewed in two stages.

Do not use a hyphen in a compound modifier formed by an adverb ending in ly plus an adjective (such as federally funded). This is true whether the compound modifier precedes or follows the noun it modifies.

Parallel construction

Parallel structure means using the same pattern of words to show that two or more ideas have the same level of importance. This can happen at the word, phrase, or clause level. The usual way to join parallel structures is with the use of coordinating conjunctions such as and or or. This is especially important when writing lists.

With the -ing form (gerund):

Correct: This program’s funding goes toward predicting, preventing, diagnosing, and treating blood disorders.

Do not mix forms, for example:

Incorrect: …funding goes toward predicting, preventing, diagnosis, and to treat blood disorders.

Changing to another pattern within a clause or changing the voice of the verb (from active to passive or vice versa) will break the parallelism. Example of parallelism with clauses:

Parallel: In our classroom, students are expected to be kind, respectful, and prompt.

Not parallel: In our classroom, students are expected to be kind, respectful, and arrive promptly.


AP Stylebook: Period

Use a single space after a period at the end of a sentence.

Quotation mark

AP Stylebook: Quotation Marks

Always place quotation marks outside periods and commas. Placement of quotation marks with question marks and exclamation points depends on whether the question or emphasis is part of the quotation.


The lecturer asked, "Are there any questions?"
What do you mean, "almost accurate"?

Put quotation marks around a word or words used in irony.

Example: The “debate” turned into a free-for-all.


AP Stylebook: Semicolon

State abbreviations

AP Stylebook: States

Spell out the state names in the body of the story.

Subject-verb agreement

Deciding whether a verb should be singular or plural is difficult sometimes.
Some guidance:

The number of, the total number of: the verb is singular.


The number of samples was unknown.
The total number of cases was hard to predict.

A number of, a total of: the verb is plural.


A number of patients were examined.
A total of 50 vials were sent to the laboratory.

As well as, in addition to, along with: the verb agrees with the main subject only.

Example: Rubella, as well as chickenpox, is contagious.

Or, neither . . . nor, either . . . or: the verb agrees with the subject closest to the verb.


The physicians or the nurse has to be present.
The physician or the nurses have to be present.

Neither the medication nor the hospital stays were helpful.
Neither the hospital stays nor the medication was helpful.

None, other quantities: the agreement of the verb is context dependent.

None of the medication was taken.
None of the symptoms were present.

Half of the pill was enough.
Half of the patients were sent home.

Note: The word data is plural and takes a plural verb form.


Not towards.

Unfamiliar terms

Writers can use quotation marks or italics to introduce an unfamiliar term on first use. Do not put subsequent references in quotation marks or italics. Either is acceptable as long as use is consistent within the same document or webpage.

Example: Energy is measured in “joules.”
Example: Energy is measured in joules.

Write short paragraphs

Short paragraphs are easier to read than long paragraphs. The white space after a paragraph gives readers a moment to absorb the material they just read before moving to the next paragraph.

Write shorter sentences whenever possible

Use short sentences to make your point clear on the first reading. People digest short sentences more easily than long sentences.

This page last reviewed on January 17, 2024