Parenthetical Plurals - AMA Manual of Style

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Parenthetical Plurals 


Stacy Christiansen

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Parenthetical Plurals

When -s or -es is added parenthetically to a word to express the possibility of a plural, the verb should be singular. However, in most instances it is preferable to avoid this construction and use the plural noun instead.


The risk factor(s) for each study participant was not always clear.


The risk factors of the study participants were not always clear.

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