Most millionaires don’t stay that way

Mark Rank, a professor of social welfare at Washington University, has written extensively on income inequality in the United States. For example, in a 2013 New York Times blog, he wrote that "Contrary to popular belief, the percentage of the population that directly encounters poverty is exceedingly high." Specifically, he says his research shows that at least 54 percent of Americans between the ages of 25 and 60 "will spend a year in poverty or near poverty (below 150 percent of the poverty line)."

But in an opinion piece in the April 20 Sunday Review section of the New York Times, Rank reveals the findings of research he conducted with Thomas Hirschl of Cornell that addresses the issue of the highest-income group in America, the 1 percent. That research shows that "12 percent of the population will find themselves in the top 1 percent of the income distribution for at least one year" during that same age range — 25 to 60. Moreover, 39 percent will spend a year in the top 5 percent, 56 percent will be in the top 10 percent and "a whopping 73 percent will spend a year in the top 20 percent of the income distribution."

Rank's conclusion is that his research "casts serious doubt on the notion of a rigid class structure in the United States based upon income." Instead, "the majority of Americans will experience at least one year of affluence at some point during their working careers." He is quick to point out that such "fluidity" of income applies to poor people, going back to his earlier data that shows 54 percent of Americans will experience poverty or near poverty during their working years. He proposes that we "shape our policies" to reflect this fluidity, and concludes that "we have much more in common with one another than we dare to realize."