Thursday, May 6, 2010

It's the maverickosity, stupid

A while I ago I asked why political scientists had such a hard time pin-pointing Sen. Russ Feingold's (D-WI) ideal point.  He seemed to be either the most liberal Democratic senator or one of the most conservative, depending on when you looked at him or how you estimated his score.

Well, Princeton PhD student Ben Lauderdale has helped to explain why this is the case in a new paper (via Monkey Cage).  Lauderdale uses roll call votes to estimate a "maverick score" for members of Congress.  This is roughly a measure of how difficult it is to classify members' votes because their behavior is so unpredictable.  Lo and behold, topping the list is our friend Russ Feingold:
John McCain was quite the maverick back in 2001-02, but today he doesn't even crack the top ten.

This strikes me as a very cool measure and a useful one.  But I suppose the next question is, what exactly are we measuring?  What does one's maverick score indicate?  McCaskill and Bayh are both in moderate-to-conservative leaning states, so maybe they have to be a little mavericky to stay in office.  But Feingold is quite safe in his seat, as is Bernie Sanders, number four on the list.  So electoral safety/vulnerability doesn't look like the cause.  (Lauderdale also notes that Rep. Barney Frank has had a pretty high maverick score throughout his career, with the exception of when he faced potential expulsion in the 101st Congress due to a scandal.  In this case, his career incentive was to be as predictable as possible.)  Is this just a personality type? 

1 comment:

jim said...

But I suppose the next question is, what exactly are we measuring? What does one's maverick score indicate?

As I read it, the difficulty in assigning an ideal point separated from the location of the ideal point itself. Otherwise, lots of moderates would appear to be "mavericky" because their predicted votes are often wrong just because their ideal points are near a lot of separating hyperplanes.

OTOH, a Democrat or Republican can still be "mavericky" in a more common-usage sense if they have an ideal point that they very consistently vote from, but that ideal point is uncharacteristic of the party. Such legislators would be (all else equal) very easy to determine the ideal point of, and so not appear in Lauderdale's measure.