Average Marginal Income Tax Rates for New Zealand, 1907-2009

Estimates of marginal tax rates (MTRs) faced by individual economic agents, and for various ggregates of taxpayers, are important for economists testing behavioural responses to changes in those tax rates. This paper reports estimates of a number of personal marginal income tax rate measures for New Zealand since 1907, focusing mainly on the aggregate income-weighted average MTRs proposed by Barro and Sahasakul (1983, 1986) and Barro and Redlick (2011). The paper describes the methodology used to derive the various MTRs from original data on incomes and taxes from Statistics New Zealand Official Yearbooks (NZOYB), and discusses the resulting estimates.