Isn't that sort of a given, though? If two people are otherwise equal, and one is better at something that will contribute even the smallest gain to your business, why wouldn't you choose him? There can be no other criteria, as they are otherwise equal.
Jesus, the advice is perfectly clear. It doesn't require logical dissection.
If you are unable to choose between two candidates, pick the candidate
who is a better writer (as opposed to a better lumberjack).
It assumes that your original method of choosing did not take into account writing proficiency, and that one candidate is a better writer than the other.
