US station manager Todd Storz twigged to the idea in the 1950s. Like most radio stations, his had been playing a bit of everything, what he thought people wanted. Then as he waited in a restaurant to pick up his girlfriend, who was a waitress, he noticed that the other waitresses were programming into the jukebox the same songs they had been hearing all day. They had come to like what they had been forced to hear. He invented Top 40 and never looked back.

But triple J is different. Its listeners have minds of their own, right?

Liam Lenten and Jordi McKenzie, economists and music tragics from La Trobe and Macquarie universities, think not.

They've just completed what is probably the only economic analysis of Australian pop music charts. Published in the Economic Record, it was intended to be a study of what kept songs at the top of the all-time Hottest 100 and what let new ones in.

The Hottest 100 comes in two forms. The annual survey, which these days is limited to tracks released in the previous year, is followed by a release of a double CD. The best tracks of all-time survey, which used to be annual, now takes place once every 10 or so years. Both are decided by popular vote.