The ideology of voters, congressmembers, and senators

Andrew Gelman has a post on some of the findings of his forthcoming and apparently very promising book, Red State, Blue State, Rich State, Poor State:

These plots from John Sides reminded me of some graphs from our forthcoming Red State, Blue State book that display the distributions of voters, House members, and senators on a common scale:


House members and senators’ positions are estimated based on their votes in Congress.  Voters’ positions are estimated based on some survey questions where people were asked their views on a number of issues that had also been voted on in Congress.  As you can see, elected representatives are generally more extreme than voters.