This paper compares the tax systems of Australia, Canada, New Zealand, the UK and the US, and summarizes the evidence about top income shares.

Australia’s top earners have increased their share of income more than three fold over the last three decades, according to updated research based on a 2006 paper. The study, conducted by ANU economist Professor Andrew Leigh from the Research School of Economics, in conjunction with Oxford University’s Sir Tony Atkinson, used taxation statistics to estimate...