Dworczak Discusses the Impact of Income Tax on Social Justice

The idea that income tax would be sufficient to promote distributive justice depends on conditions that are rarely met in practice. This was one of the main issues discussed by economist Piotr Dworczak, of Northwestern University and the Group for Research in Applied Economics, during his lecture Optimal Redistribution via Income Taxation and Market Design, presented this Tuesday (the 14th) at the 25th Annual Conference of the Society for the Advancement of Economic Theory (SAET).

The researcher presented a study analyzing the relationship between taxation, redistribution, and market design, highlighting the limitations of a classic finding in economic theory that holds that it is possible to separate the objectives of efficiency and equity. In other words, leaving markets responsible for the efficient allocation of resources and using income tax as the primary instrument to promote distributive justice.

The study’s main contribution is to show that this distinction between efficiency and redistribution does not always hold true in practice. When people’s needs vary for reasons beyond income, income tax alone may not be sufficient to promote distributive justice. In such cases, policies aimed at the functioning of certain markets also come to play an important role.

As an example, Dworczak cited the healthcare market. “If the only reason for wanting to pay more for healthcare were that I am wealthier, it would still be true that income tax alone would suffice. But the problem is that, in general, the poorest people also have a greater need for health care, because they tend to face more difficult living conditions and have poorer health. When these two characteristics combine—lower ability to pay and greater need—it becomes important to intervene directly in this market,” he explained.

Piotr Dworczak

According to Carlos da Costa, a professor at the Getulio Vargas Foundation (FGV), who attended the presentation, the study highlights the limitations of a traditional view of the economy.

“There is a finding in economics that suggests markets, in general, are the best institution for ensuring efficiency. At the same time, we recognize that they do not necessarily promote equality. This gives rise to the idea of letting the market handle efficiency and using income tax to address the distributional problem. The point of the article is to show that the conditions under which this is true are very restrictive,” he said.

The lecture was chaired by economist Jeff Ely, also from Northwestern University, and concluded Tuesday’s (14) presentations at IMPA. The 25th SAET is bringing together researchers from different countries at IMPA through next Saturday (18) to discuss advances in economic theory and celebrate the 80th birthday of Aloisio Araujo, one of the leading figures in Brazilian mathematical economics.