James Pethokoukis highlights a number of ways in which concerns about income inequality are mostly an artifact of overly broad statistical measures:

A pair of studies from 2007 and 2008 conducted by the Federal Reserve Bank of Minneapolis supports Gordon. Researchers examined why the Census Bureau reported median household income stagnated from 1976 to 2006, growing by only 18 percent. In contrast, data from the Bureau of Economic Analysis showed income per person was up 80 percent. Like Gordon, they found apples-to-oranges issues such as different ways of measuring prices and household size. But in the end, they concluded that “after adjusting the Census data for these three issues, inflation-adjusted median household income for most household types is seen to have increased by 44 percent to 62 percent from 1976 to 2006.” In addition, research shows that median hourly wages (including fringe benefits) rose by 28 percent from 1975 to 2005.

A 2008 paper by Christian Broda and John Romalis from the University of Chicago documents how traditional measures of inequality ignore how inflation affects the rich and poor differently: “Inflation of the richest 10 percent of American households has been 6 percentage points higher than that of the poorest 10 percent over the period 1994–2005. This means that real inequality in America, if you measure it correctly, has been roughly unchanged.”

A 2010 study by the University of Chicago’s Bruce Meyer and Notre Dame’s James Sullivan notes that official income inequality statistics indicate a sharp rise in inequality over the past four decades: “The ratio of the 90th to the 10th percentile of income, for example, grew by 23 percent between 1970 and 2008.” But Meyer and Sullivan point out that income statistics miss a lot, such as the value of government programs and the impact of taxes. The latter, especially, is a biggie. The researchers find that “accounting for taxes considerably reduces the rise in income inequality” over the past 45 years. In addition, “consumption inequality is less pronounced than income inequality.” (emphasis in original)