Welcome to AP vs. Chicago: A Style Guide for Editors, Writers, and Word Nerds
by Karen Yin
A copy editor with 20-plus years of experience, I make it my job to keep up with changing styles and the evolution of language (or devolution, as the case may be). Even if my client doesn’t claim allegiance to any style, I will go along with the style they’ve arbitrarily created and shake out the mess of commas, hyphens, capitals, and italics to create a piece that sings with power and clarity. And for websites, advertisements, letters, and résumés, this is what makes what you’re selling shine.
It seems as if I’m always rifling through my reference books to check whether a compound is open, hyphenated, or solid in a particular style.
I’m going to focus on the difference between how The Associated Press Stylebook and The Chicago Manual of Style handle possessives for words ending in s or an s sound.