Income Growth Despairity

I am taking a fascinating class right now in microeconomics. This wasn't my favorite class as an undergrad but at a public policy school you get the chance to think about some basic principles of economics in terms of policy (of course) and how making certain policy decisions will have certain impacts. Today we were discussing various types of efficiency models and comparing efficiency and equity.

Over the last 20-30 years people have debated the efficacy of trickle-down economics. The question is does trickle-down economics do what its name implies? Does it trickle down and reach those at the lower strata of the socio-economic classes? What I saw in class today seemed to suggest convincingly that it doesn't and in fact did more to create income growth inequity than any other economic policy between 1947 and 1979.

Take a look at the following slide from today's lecture.



Now look at the data between 1980 and 2005.



Leaves an impression, huh?