Basic rules for forming possessives
Singular nouns
To form the possessive of a singular noun not ending in an "s" sound, add an apostrophe s.
a child's wants
women's health
everyone's answer
Gloria's career
To form the possessive of a singular noun that ends in an "s" sound, pay attention to the way the word is pronounced.
If a new syllable is formed in the pronunciation of the possessive, add an apostrophe s.
her boss's approval
the witness's reply
Congress's intervention
Ms. Lopez's overall condition
Phoenix's patient demographic
If the addition of an extra syllable would make a word ending in "s" hard to pronounce, add the apostrophe only.
Texas' Medicare population
Los Angeles' freeways
Brahms' symphonies
Dr. Gates' treatment plan
Plural nouns
For regular plural nouns (one that end in s or es), add only an apostrophe to form the plural possessive.
investors' objectives
the witnesses' contradictions
an old boys' network
the Darlings' grandchild
attorneys' fees
Since the singular and plural possessives for the same word usually sound exactly alike, pay close attention to the meaning in order to determine whether the noun in question is singular or plural.
A patient's condition should largely define treatment strategy.
Patients' motives are not always clear.
For irregular plural nouns (ones that do not end in s), add apostrophe s to form the plural possessive.
women's issues
men's diseases
children's immunology
If a proper noun or name ends in a silent s, z or x, form the possessive by adding apostrophe s.
Theroux's work was showcased
Ms. du Pres's case was reviewed
Compound terms
To form the singular possessive of a compound noun, whether solid, spaced or hyphenated, add apostrophe s only after the last word of the compound term.
father-in-law's health
someone else's problem
chief medical officer's decision
department head's responsibility
the eyewitness' account
a do-it-yourselfer's obsession
Food and Drug Administration's policy
Centers for Disease Control and Prevention's Task Force
To form the plural possessive of a compound noun, first form the plural.
If the plural form ends in s, add only an apostrophe.
Singular / Plural / Plural Possessive
vice president / vice presidents / vice presidents'
wheeler-dealer / wheeler-dealers / wheeler-dealers'
salesclerk / salesclerks / salesclerks'
If the plural form does not end in s, add an apostrophe s.
Singular / Plural / Plural Possessive
chief of staff / chiefs of staff / chiefs of staff's
brother-in-law / brothers-in-law / brothers-in-law's
NOTE: To avoid awkwardness of a plural possessive such as chiefs of staff's or brothers-in-law's, rephrase the sentence.
Awkward: We may have to invite the three chiefs of staff's administrators.
Better: We may have to invite the administrators to the three chiefs of staff.
Awkward: The patient's statement agrees with both attending physicians' views.
Better: The patient's statement agrees with the views of both attending physicians.
Joint and Individual Possession
When a sentence indicates joint ownership in a compound construction, the possessive form is attached only to the second noun.
Deanna and Brandi's vacation plans
Tim and Bethany's wedding invitation
Note that individual ownership is marked by a double possessive:
Courtney's and Mem's grade point averages
Tim and Bethany share the same wedding invitation, whereas Courtney and Mem each have their own grade point averages.
We matched the infant's and mother's records.
The physician's and resident's signatures were obtained.
Possessive pronouns already indicate ownership. Do not add 's to them.
The idea was hers.
It was his book.
Hers is a long and complicated course.
When one of the nouns takes a possessive pronoun, the other nouns take the possessive as well.
I presented the intern's and my workups.
It was the patient's and my intent to proceed.
His recommendations were congruent with the chief of surgery's.
Some indefinite pronouns have regular possessive forms.
one's choice
anyone else's job
anybody's guess
no one's responsibility
When forming the possessive, be sure to place the apostrophe correctly.
the other's claim (only one person involved)
the others' claim (more than one person involved)
each other's claim NOT each others' claim
For indefinite pronouns that do not have possessive forms, use an of phrase.
Although the children in the group seem very much alike, the needs of each are different. (NOT: each's needs)
To be sure that the possessive form should be used, try substituting the phrase or making a similar substitution. If the substitution works, the possessive form is correct.
A two weeks' course (meaning a course for or lasting two weeks)
my boss's approval (meaning the approval of my boss)
Do not mistake a descriptive form ending in "s" for a possessive form.
sales effort (sales describes the kind of effort)
new release (news describes the type of press release)
Some cases can be difficult to distinguish. Is it the girls basketball team or the girls' basketball team? Try substituting an irregular plural, like women.
the women basketball team
Correct: The women's basketball team
Therefore: the girls' basketball team is correct.
In some cases, only a slight difference in wording distinguishes a descriptive phrase from a possessive phrase.
Descriptive: a six-month course of treatment
Possessive: a six months' course of treatment
Descriptive: the California climate
Possessive: California's climate
Descriptive: the Crosby children
Possessive: the Crosby's children OR: Mr. and Mrs. Crosby's children
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