Q. I’m having a long debate with a writer about the following usage: “Each sister was prettier than the next.” As an editor, I say that as stated, it means that the sisters got uglier on down the line, which was not what the author intended. I say it should be “Each sister was prettier than the one before.”
A. You are right; this is a common error: it should be either “prettier than the one before” or “prettier than the last.”