Reduced Tax Progressivity in Norway in the Nineties: The Effect from Tax Changes

The inequality in pre-tax income increased in Norway in the 1990s, while the concentration of taxes remained largely unaltered. This means that tax progressivity has decreased in the period, as measured by summary indices of tax progressivity. In this paper I analyze individual income data to ascertain whether tax changes in the period can explain the observed decrease in tax progressivity. As marginal tax rates at high income levels have been substantially reduced in the period, for instance through the tax reform of 1992, it is expected that tax changes may have influenced the degree of inequality in pre-tax incomes. This behavioral effect is examined by deriving estimates of the elasticity of gross income with respect to the net-of-tax rate, obtained from various panel data regressions. The tax changes may also have shifted the distributional burden of taxes for unaltered level of pre-tax income inequality. In order to identify this (direct) effect of tax-law alterations, the same fixed distribution of pre-tax income is exposed to various tax-laws in the period.