A 2009 study in the British Medical Journal attempted to quantify the number of deaths that could be attributed to economic inequality among the 30 rich countries that make up the Organization of Economic Cooperation and Development (OECD). The researchers found an association between greater inequality and a higher overall death rate in countries where inequality runs relatively high.
What constitutes “relatively high” inequality? To answer this question, the researchers ranked the 30 OECD countries in order of their “Gini index,” a standard metric that economists use to describe the level of inequality in a population. Ginis can run from 0.0 to 1.0, with higher numbers indicating greater inequality.
The most equal country in the OECD, Denmark, has a Gini of 0.225. The United States ranks as the fourth-most unequal country, with a Gini of 0.357, following only Mexico, Turkey, and Poland. The median Gini among OECD nations, 0.3, became the reference point against which researchers compared countries and their death rates.
The study concluded that almost 884,000 excess deaths per year in the United States could be attributed to the high level of income inequality in the U.S. In other words, if the Gini in the United States were 0.3 instead of 0.357, we would see nearly 884,000 fewer deaths per year.