There is another statistical trick with the numbers that biases the results in favor of measuring income gains for those at the very top of the income scale. When a poor person over time moves into the middle class or the upper class, that person no longer is classified as poor. So, for example, someone who was earning $20,000 a year and then got a big promotion and saw their income move to $50,000 as they moved up the job ladder, experienced a 150 percent gain in income, but it doesn’t count as a gain to the poor because the household is no longer poor. So if a poor person makes $1 million as an athlete or a business owner, we count that person as rich, not as having been poor. But at the same time, every penny of income gain by a rich person is counted because there is no higher income class to move into.
From Who’s The Fairest of Them All? By Stephen Moore
The data on income distribution is subject to a basic understanding of statistics that is omitted from most reporting on the problem. Our leaders also understand the data poorly. Some data is selected to prove a political point rather than to illuminate a reality. When the facts do not support the theory the demagogues hide the inconvenient facts and double down on the theory.