Anthony Davies is associate professor of economics at the Palumbo Donahue School of Business at Duquesne University, and presents the podcast Words and Numbers, and has written many research papers including this one which I mentioned in the podcast.

I’ve checked the sources, and it is clear that while real wages have risen slightly, they have risen sharply for the top 10 per cent of earners, and declined for the bottom 10 per cent.

In addition, the link between productivity and wages was broken in the mid-1970s and has not been restored since – as workers get more and more productive, producing more and more for their employers, their wages remain largely flat in real terms.

The Gini coefficient is mathematical a measurement of the the level of inequality of income inequality in a country, city, or any other unit.  It has risen sharply in the United States since about 1990. As I said in the podcast, there is a correlation between the level of inequality in a society and the level of violence as noted here, here and here.