A prosperous middle class is central to economic productivity and income inequality is a threat to our economic and political health

 Heather Boushey and Adam Hersh at Center for American Progress:

To say that the middle class is important to our economy may seem noncontroversial to most Americans. After all, most of us self-identify as middle class, and members of the middle class observe every day how their work contributes to the economy, hear weekly how their spending is a leading indicator for economic prognosticators, and see every month how jobs numbers, which primarily reflect middle-class jobs, are taken as the key measure of how the economy is faring. And as growing income inequality has risen in the nation’s consciousness, the plight of the middle class has become a common topic in the press and policy circles.

For most economists, however, the concepts of “middle class” or even inequality have not had a prominent place in our thinking about how an economy grows. This, however, is beginning to change. One reason for the change is that the levels of inequality and the financial stress on the middle class have risen dramatically and have reached levels that motivate a closer investigation. The interaction and concurrence of rising inequality with the financial collapse and the Great Recession have, in particular, raised new issues about whether a weakened middle class and rising inequality should be part of our thinking about the drivers of economic growth.