This article is three years old (I just saw it) and the study it cites is from 2002. That makes things worse than they say. It's about scientific proof we are an oligarchy rather than a democracy. The main criteria is how often what the People want does not get to happen. We must work together to change this.
Find it here: http://www.dailykos.com/stories/2014/4/14/1292085/-DINO-New-Scientific-Study-Says-Yes-But-It-s-Not-What-You-Think