Writing Sentences: Punctuation Errors: Missing, unnecessary or misplaced apostrophes

Some of the most common errors in punctuation relate to using apostrophes to signal ownership or possession.

The general rule governing the use of apostrophes to signal ownership in all nouns is that:

The book's cover was considered radical at the time. The colony's social and economic problems were ...	Singular Noun: the apostrophe follows the owner of the cover, the book.
The books' covers were considered radical at the time. The colonies' social and economic problems were ...	Plural Noun: the apostrophe follows the owner of the covers, the books.
This thesis's contention that ... James's results suggested that ...	Singular Noun ending in s: the apostrophe follows the owner of the contention, the thesis.
The children's scores on the memory test suggested ... The people's political party was formed to ...	Plural Nouns that do not end in the letter s: the apostrophe follows the owner of the scores, the children.
Mathews, Martin, and Gilroy's research claimed ... The steel workers and engineer's wage claim was ... NOTE: In a list of nouns only the final noun in the list, rather than all the nouns, has an apostrophe added to signal ownership.	List of nouns: the apostrophe follows the final owner of the research in the list of owners, in this case Gilroy.