Stanford’s Charles Jones corrects glaring shortcomings in the Diamond/Saez’s optimal tax analysis to show why top marginal tax rates of 30% or less likely maximize social welfare in an innovation-driven economy. Jones concludes:
“Because ideas are nonrival, each person’s wage is an increasing function of the entire stock of ideas. A distortion that reduces the production of new ideas therefore impacts everyone’s income, not just the income of the inventor herself. These conditions lead to a new term in the Saez (2001) formula for the optimal top tax rate: by slowing the creation of the new ideas that drive aggregate GDP, top income taxation reduces everyone’s income, not just the income at the top. When the creation of ideas is the ultimate source of economic growth, this force sharply constrains both revenue-maximizing and welfare-maximizing top tax rates. For example, in a baseline calculation, the revenue-maximizing top tax rate that ignores the innovation spillover is 92%. In contrast, the rate that incorporates innovation and maximizes a utilitarian social welfare function is just 29%. Moreover, if ideas play an even more important role than assumed in this baseline, it is possible for the optimal top income tax rate to turn negative: the increase in everyone’s income associated with subsidizing innovation exceeds the gains associated with redistribution.”