U.S. members of Congress tend to “die in their ideological boots” as Keith Poole puts it. This is probably true for most legislators around the world. Yet, there are some contexts in which legislators shift positions and even parties with great frequency. Howard Rosenthal and I wrote a paper (ungated) a while back about one such context: The French Fourth Republic. There were frequent changes in government coalitions and about one-fifth of legislators switched parties at some point. Adam Bonica, a very bright PhD student at NYU, has created a cool animation of the movements by legislators through a two-dimensional ideological space based on this data. The animations are based on this paper in which he advances the methodology of estimating dynamic ideal points in a non-parametic framework. It’s fun to watch, especially for people who have seen similar types of animations from other legislative settings: it really drives home just how unstable the Fourth Republic was and why it is often used as an example of how one should not design legislative institutions (although the institutions were only partially responsible for this).
The animations work best if you enlarge the screen. Btw, Adam’s site is a great example of how to use ones blog to publicize ones research.
