If you say it, spell it

When forming possessives, it is a common misconception that the s is dropped for singular nouns ending with -s. Whereas, in most cases, the final s is retained, as in “Bridget Jones’s Diary”. In this case, the singular possessive is pronounced Jones-es, so it’s spelled Jones’s. Just remember: if you pronounce it, then you write it. Similarly, Chris’s and chess’s take the final s, but Andrews’ (as in Kevin Andrews’ mistake) does not (because that’s how they are pronounced).

The confusion probably comes from the rule for forming possessives of plural nouns ending with s, which take the apostrophe only, such as “a parents’ retreat” and “the Joneses’ driveway”.

Another common error is to include an apostrophe when forming plurals of acronyms. For example, NPVs is the plural of NPV (“a comparison of NPVs is given in Table 3”) and not NPV’s, which is the possessive, not the plural, of NPV.

One final tip is to avoid making possessives of inanimate objects (e.g. a table, car or tool). In such cases, use the preposition “of” (e.g. the top of the table) or form a noun stack (e.g. the table top). Possession is generally reserved for nouns involving living things, such as people, organisations, and animals, and abstract terms, such as nations, concepts, and time (e.g. the company’s values, the mosquito’s life cycle, Britain’s role, a day’s work, the project’s scope).