INCOME TAX PROGRESSIVITY IN THE UNITED STATES: NEW EVIDENCE, 1969–1995

New measures of the degree of overall income tax progression in the United States are provided for the period 1969 to 1995. Indices of progression from the distributional and tax scale invariant classes of measures are considered. The sensitivity of measures of progression to the income concept used and to equivalence scale adjustments is explored. Recently developed statistical inference procedures are applied to reveal new insights into changes in progressivity across time. Using a microdata based measure of comprehensive income and applying statistical tests are shown to be of crucial importance in reaching conclusions about changes in income tax progression.