The BBC is featuring a piece about a report by Princeton University Prof Martin Gilens and Northwestern University Prof Benjamin I Page on the influence citizens of the U.S. have on policy, based on income level.
http://www.bbc.com/news/blogs-echochambers-27074746
In this report, the professors looked at answers to survey questions between 1981 and 2002 and broke down the answers according to income level. Then they looked at which income level had the most influence on policy decisions.
http://www.princeton.edu/~mgilens/Gilens%20homepage%20materials/Gilens%20and%20Page/Gilens%20and%20Page%202014-Testing%20Theories%203-7-14.pdf
Abstract:
"Each of four theoretical traditions in the study of American politics – which can be characterized as theories of Majoritarian Electoral Democracy, Economic Elite Domination, and two types of interest group pluralism, Majoritarian Pluralism and Biased Pluralism – offers different predictions about which sets of actors have how much influence over public policy: average citizens; economic elites; and organized interest groups, mass-based or business-oriented.
A great deal of empirical research speaks to the policy influence of one or another set of actors, but until recently it has not been possible to test these contrasting theoretical predictions against each other within a single statistical model. This paper reports on an effort to do so, using a unique data set that includes measures of the key variables for 1,779 policy issues.
Multivariate analysis indicates that economic elites and organized groups representing business interests have substantial independent impacts on U.S. government policy, while average citizens and mass-based interest groups have little or no independent influence. The results provide substantial support for theories of Economic Elite Domination and for theories of Biased Pluralism, but not for theories of Majoritarian Electoral Democracy or Majoritarian Pluralism."
They conclude that the system as is strongly favours the economical elite compared to the average citizen, and that while citizens of the U.S. "do enjoy many features central to democratic governance, such as regular elections, freedom of speech and association and a widespread (if still contested) franchise [...] if policymaking is dominated by powerful business organisations and a small number of affluent Americans, then America's claims to being a democratic society are seriously threatened."