QUOTE : The distribution of income in a society is called the 'Gini coefficient,' named after an Italian sociologist named Corrado Gini, who published a paper on the topic in 1912. A society where one person earns all the money and everyone else earns none, effectively has a Gini coefficient of 1.0; and a society where everyone earns the same amount has a coefficient of zero. Neither is desirable. Moderate differences in income motivate people because they have a reasonable chance of bettering their circumstances, and extreme differences discourage people because their efforts look futile. A study of 21 small-scale societies around the world found that hunter-gatherers like the Hadza—who presumably represent the most efficient possible system for survival in a hostile environment—have Gini coefficients as low as .25. In other words, they are far closer to absolute income equality than to absolute monopoly. Because oppression from one's own leaders is as common a threat as oppression from one's enemies, Gini coefficients are one reliable measure of freedom. Hunter-gatherer societies are not democracies—and many hold women in subordinate family roles—but the relationship between those families and their leaders is almost impervious to exploitation. In that sense, they are freer than virtually all modern societies. According to multiple sources, including the Congressional Budget Office, the United States has one of the highest Gini coefficients of the developed world, .42, which puts it at roughly the level of Ancient Rome. (Before taxes, the American Gini coefficient is even higher—almost .6—which is on par with deeply corrupt countries like Haiti, Namibia, and Botswana.) Moreover, the wealth gap between America's richest and poorest families has doubled since 1989. Globally, the situation is even more extreme: several dozen extremely rich people control as much wealth as the bottom half of humanity