John Stossel: It's income mobility that matters

More on why income inequality shouldn't matter (reason.com):

It's true that today the rich are richer than ever. And the wealth gap between rich and poor has grown. Now the top 1 percent own more assets than the bottom 90 percent!

But focusing on this disparity ignores the fact that over time, the rich and poor are not the same people. Oprah Winfrey once was on welfare. Wal-Mart founder Sam Walton was a farmhand. When markets are free, poor people can move out of their income group. In America, income mobility, which matters more than income inequality, has not really diminished.

Economists at Harvard and Berkeley crunched the numbers on 40 million tax returns from 1971-2012 and discovered that mobility is pretty much what The Pew Charitable Trusts reported it was 30 years ago.

Today, 64 percent of the people born to the poorest fifth of society rise out of that quintile—11 percent rise all the way into the top quintile. Meanwhile, 8 percent of people born to the richest fifth fall all the way to the bottom fifth.

The poor got richer, too [...] over the last 30 years, incomes of rich people grew by more than 200 percent, but according to the Congressional Budget Office, poor people gained 50 percent. That growth should matter more than the disparity. Piketty's data reveal times in our history when income inequality decreased: during world wars and depression. Do we want more of that?