Original sentence: Economist Michael Stroup disagrees with the claim that progressivity has decreased, and criticizes Saez for failing to propose an objective, cardinal measure by which to quantify the degree of tax progressivity, and for not analyzing the entire population, particularly the much larger segment on the lower end who saw tax rate drops over the same period.Other contributors to the loss of progressivity included cuts in estate taxes and a shift in wealthy households from capital to labor income, according to their work
Edited sentence: " Other contributors to the loss of progressivity included cuts in estate taxes and a shift in wealthy households from capital to labor income, according to their work.According to Piketty and Saez, "The largest reductions in tax progressivity since the 1960s took place primarily during two periods: the Reagan presidency in the 1980s and the Bush administration in the early 2000s.According to Stroup, Piketty and Saez "focus on the declining average tax rate facing the highest 1 percent of income earners to claim that federal tax policy in general has declined during this period.However, economist Michael Stroup disagreed with Piketty and Saez's study, finding their methodology to be flawed - particularly stating that their study did not properly take into account lower-bracket tax rate drops over the same period.However, their data also indicate that a lower-income segment with a much larger population also experienced falling average tax rates over this period.They allow the influence of those few with the greatest incomes in one population segment to prevail in determining the degree of overall tax progressivity simply because they command a much larger portion of national income than the more populous but poorer income segment