Horizontal equity can be determined by comparing the
Effective tax rate of the taxpayer with the highest nominal income to the effective tax rates of taxpayers with lower nominal incomes.
Marginal tax rate of the taxpayer with the highest nominal income to the marginal tax rates of taxpayers with lower nominal incomes.
Marginal tax rates for two taxpayers with the same nominal incomes.
Effective tax rates for two taxpayers with the same nominal incomes.