Note: Error bars are used to indicate the error, or uncertainty, in a reported measurement.
Why is this important?
Income inequality, or the extent to which income is unevenly distributed across a population, has been increasing in the United States for more than thirty years. An unequal distribution of income can undermine the fairness of political institution and the economic system. In a population with an unequal distribution of income, workers are denied a claim to the share of what they helped to produce.The impacts of income inequality have been studied by a number of economist. For example, Joseph Stiglitz has demonstrated that widely unequal societies are less efficient, less stable, and less sustainable in the long term.[i]
The gini coefficient, the most commonly used measure of inequality, measures the extent to which the distribution of income among individuals or households deviates from a perfectly equal distribution. In a perfectly equal system, the gini coefficient would be zero, with a gini coefficient of 100 would be the least equal distribution possible.
[i] Joseph Stiglitz, 2012. "The Price of Inequality: How today's divided society endangers our future," WW Norton & Company.