How large is the Bradley effect and does it matter for Obama?
David Strömberg
Nov 03, 2008
http://voxeu.org/index.php?q=node/2514
Will tomorrow’s US presidential election be closer than expected because Barack Obama is African-American? This column looks at the last decade of US electoral contests with black candidates and says that there is a Bradley effect, in which African-American candidates garner lower vote shares than predicted by opinion polls. If that holds true, it will be close tomorrow.
Should Barack Obama worry about the Bradley effect? The much-discussed effect refers to observed discrepancies between voter opinion polls and election outcomes, in which African-American candidates receive a smaller vote share than would be predicted using opinion polls. In this column, I study US congressional and gubernatorial contests from 1998 to 2006 – black candidates on average receive a 2-3% lower share of the two-party vote than non-black candidates with similar numbers in the polls. If an effect of a similar size would appear in the current presidential race, then it would lower Obama’s probability of winning from 85% to 53%. However, black Republican candidates drive the result, so it may not apply to Obama’s campaign.
Data
My sample includes 431 elections for the offices of House, Senate and Governor 1998-2006 for which I have election and opinion poll data and information on whether the candidate was black. The data on elections was provided by Jim Snyder at MIT, the data on candidate race is from the Joint Center for Political and Economic Studies, and the polling data was gathered from various sources. This data is similar to that of Daniel Hopkins (2008), who uses data from 133 gubernatorial and Senate elections from 1989-2006.
There are 26 black candidates in the sample, 17 Democrats and 9 Republicans (4 in gubernatorial races, and 11 each for the offices of House and Senate). I will only analyse races where a black candidate ran against a candidate who was not black. This eliminates two races, one of which is Barack Obama’s race for Senator of Illinois against Alan Keyes in 2004. I am left with 22 races. The relevant sample of 22 elections is quite small, so all results should be taken with a grain of salt (still, the sample is larger than existing studies).
The 2-3% Bradley effect
Figure 1 shows the relationship between polling and vote outcomes for races for House, Senate and Governor 1998-2006. I only include polls performed from August to the date of the election. Each dot shows the poll and vote average within each two-percent opinion poll interval, 0-2, 2-4, etc. The grey dots are non-black candidates, the blue dots are black Democratic candidates, and the red dots are black Republican candidates. The grey line shows the fitted values of a regression of Democratic vote share on Democratic poll share, for non-black candidates. As you can see, black candidates on average do worse than other candidates polling at the similar numbers in the polls: Democratic black candidates more often lie below the regression line (expected vote, conditional on poll) and Republican black candidates more often lie above.
[contd.]
Internet Censorship Alert
Internet Censorship Alert: Alex Jones exposes agenda to 'blacklist' dissenting sites (March 14, 2010)
As I predicted, the Obama Administration is trying to shut down the Internet - at least the parts he doesn't like. Barack Obamas regulatory czar, Cass Sunstein has stated that he wants to ban conspiracy theories from the internet. Think about what this means - Every video, every website, every blog, every email, that exposes or just criticizes the government for any reason whatsoever could be labeled a "conspiracy" and taken down. Your home could be raided in the middle of the night, and you could be carted of to jail for criticizing the government. All they have to do is call it a "conspiracy theory".
http://www.youtube.com/watch?v=aqAWmBLFodE
Wednesday, November 5, 2008
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