  Concern about income inequality has become prominent in public discourse
around the world. However, studies in behavioral economics and psychology have
consistently shown that people prefer not equal but fair income distributions.
Thus, finding a benchmark that could be used to measure fair income
distribution across countries is a theoretical and practical challenge. Here a
method for benchmarking fair income distribution is introduced. The benchmark
is constructed based on the concepts of procedural justice, distributive
justice, and authority's power in professional sports where it is widely agreed
as an international norm that the allocations of athlete's salary are outcomes
of fair rules, individual and/or team performance, and luck in line with
no-envy principle of fair allocation. Using the World Bank data, this study
demonstrates how the benchmark could be used to quantitatively gauge whether,
for a given value of the Gini index, the income shares by quintile of a country
are the fair shares or not, and if not, what fair income shares by quintile of
that country should be. Knowing this could be useful for those involved in
setting targets for the Gini index and the fair income shares that are
appropriate for the context of each country before formulating policies toward
achieving the Sustainable Development Goal 10 and other SDGs.
