There's an old saying in marketing that half of all marketing works, but nobody knows which half. That's likely an outdated metric, what with the new army of data scientists and algorithms that didn't used to exist, but there are still plenty of places where art is called for more than science. Take for example movie advertising, my old bailiwick. When deciding what tagline to put on a poster, or which review quotes to include in an ad, it's mostly hunch.…