Arizona’s House is strikingly partisan. There’s a big ideological gap between Democrats and Republicans and the one Democrat in the middle — Norma A. Muñoz — has had virtually no success getting legislation through.

That’s one of many takeaways from a new Sunlight Foundation interactive that charts partisanship, effectiveness at passing bills and cooperation among most of the nation’s state legislators. The chart, posted Tuesday by developer Thom Neale and embedded below, is a pretty good visualization of the increasing partisanship in state capitals. It shows three things:

  1. The X-axis shows each state chamber’s partisanship. Each legislator is represented by a circle, and, using a standard political science technique known as ideal point estimation, Neale plots them along a liberal-conservative spectrum. Some argue that such scales don’t accurately capture ideology, and there are some quirks. (In at least one state, Rhode Island, the data displays with conservatives on the left and liberals on the right, for example.) Still, the measure gives a decent sense of relative ideology— how each state legislator compares with his or her peers.
  2. The Y-axis shows each legislator’s success at passing bills. The higher up a legislator’s circle is placed, the better their track record at passing bills. To minimize the impact of what he calls “theatrical bills” — the kind with little substance that serve as political messaging — Neale assigned greater weight to bills that were subsequently signed by the governor into law. Again, the measure isn’t foolproof. Some state legislative staffers pushed back on his weighting system, and measuring impact is difficult. But, again, it shows relative effectiveness rates for each legislator.
  3. The size of each circle reflects how often a legislator’s peers sign onto their bills. 

All data weren’t available for all states, which explains why in some chambers all circles are sized equally  and/or placed along the same level. But the chart reveals a lot about partisanship and cooperation in U.S. legislatures. Hover over any circle for more information about each legislator.