Monday, October 27, 2008

Bradley Effect? Or Elephant Effect?

Thank you!

I'm pretty sure that everyone who visits this blog and the blogs I link to has heard of the "Bradley Effect" in the past few months. The Bradley Effect purports to be an explanation of the gap between polling figures for black candidates and their actual, lower, vote totals on election day. There's been plenty of discussion the role that race and racial attitudes might play in this election.

My eldest daughter, while looking at some recent poll numbers with me, repeated the phrase "cautious optimism, cautious optimism" several times while viewing. While we were flipping through some polling and politics websites, I found this piece by Nate Silver of FiveThirtyEight:

Bradley Effect? Or Elephant Effect?

The piece responds to an article by Republican consultant Bill Greener in Silver pretty much takes apart Greener's hypothesis that a "Bradley Effect" occurred in several gubernatorial and senate elections in 2006, involving black candidates.

Silver's conclusion?

Three of the five profiled black candidates were Republicans, running in an election year that was, well, pretty bad for Republicans:
The year 2006, as you may recall, was a very one for Republicans. Democratic candidates overperformed their poll in a significant majority of competitive races around the country.

In fact, there were other races going on at the same time in Maryland and Ohio, both of which involved two white candidates. In Maryland, there was also a race for Governor; the Democrat, Martin O'Malley, was projected by the RCP average to defeat the Republican, Robert Ehrlich, by 1.3 points. In fact, O'Malley won by 6.5 points. In Ohio, meanwhile, the Democratic candidate for Senate, Sherrod Brown, was projected by RCP to defeat the Republican, Mike DeWine, by 10.0 points. In fact, Brown won by 12.3 points.

So, it wasn't just black Republicans who were undeperforming their polls; it was white Republicans too (likewise with Rick Santorum in Pennsylvania): not a 'Bradley Effect' so much as an 'Elephant Effect'.

But it wouldn't please a Republican consultant to talk about that, now would it?


Grant Miller said...

I read 538 ALL THE TIME. I almost don't want this election to happen because I won't have anything to focus on anymore.

vikkitikkitavi said...

I read Greener, and then was happy to see him refuted on 538, which I also monitor constantly. I don't believe in the Bradley effect, and I was relieved to see Silver point out that everyone who does pretty much cherry-picks their examples.