The American Society of Composers, Authors and Publishers (ASCAP) sells blanket licenses for music that are created by individual music creators. How does ASCAP calculate each individual composer's share? I understand they conduct sample surveys, but if some piece of music isn't used sufficiently, it might be completely missed, although otherwise the royalties may not be negligible. Also, if a piece of music is tailored for restaurants or bars, how would it be reckoned? ASCAP doesn't seem to survey restaurants or bars.
Am I missing anything here?
Disclaimer: I'm not a musician but interested in understanding some industry practice.