What factors determine audience size?
As so many have before him, music critic Michael Dervan of the Irish Times Culture tries to divine what determines audience size at a concert. He doesn't comes up with anything surprising, but it's always worth getting a new perspective.
The reality is, this question has a different answer in every city and is affected by a myriad of factors. If you don't get to know your audience (through a combination of surveys and long-term attendance analytics), you're flying blind and taking stabs in the dark when projecting attendance (and revenue!).