From the beginning, Pandora has banked on a proprietary music rating system called the Music Genome Project. It involves rating songs on hundreds of attributes, from “aggressive drumming” and “jazz influences” to “angry lyrics” and “ambiguous soundscapes.” These ratings are given by trained musicologists — people who are musicians themselves, many of whom have advanced degrees in music — and it takes about 12 to 15 minutes per song.  We wanted to know: Was it worth it? Learn more about your ad choices. Visit megaphone.fm/adchoices