Saez has written extensively on the theory of
optimal taxation and transfer, addressing topics such as wealth and income inequality, capital income taxation, and retirement. In addition to his theoretical work, he has authored a number of empirical papers, many of them applying the results from his theoretical work to US household data. His focus on the top 0.1% of the income and wealth distribution has led to his political theories about the "great compression" and the "great divergence" and led to significant research on the consensus about the ideal wealth distribution. Saez's research on wealth and
income inequality has largely focused on households at the top of the wealth and income distributions, which make up a significant portion of the US tax base. Critics, such as James Pethokoukis of the
American Enterprise Institute, say that Saez and Piketty measure "market income," the total income before tax excluding income from government. Saez describes it as gross income reported on tax returns before any deductions. This excludes unemployment insurance, welfare payments, food stamps,
Medicare,
Medicaid, Social Security and employer-provided health insurance. Saez says that these are the best data available, as measured consistently since 1913. Critics say that they exaggerate inequality. In 2011, Saez and
Peter Diamond argued in public media a widely discussed paper that the proper marginal tax rate for North Atlantic societies and especially the United States to impose is 73% (substantially higher than the current 42.5% top US marginal tax rate). Together with
Raj Chetty and others he researched
social mobility in the US. They found substantial geographic differences across the country that were correlated with five factors: segregation,
income inequality, local school quality, social capital, and family structure. ==Awards==