Poll accuracy in the 2008 presidential election: Rasmussen, Pew

For all the derision directed toward pre-election polling, the final poll estimates were not
far off from the actual nationwide voteshares for the two candidates. On average, preelection
polls from 23 public polling organizations projected a Democratic advantage of
7.52 percentage points on Election Day, which is only about 1.37 percentage points away
from the current estimate of a 6.15-point Obama margin in the national popular vote.
Following the procedures proposed by Martin, Traugott and Kennedy (see Public Opinion
Quarterly, Fall 2006, pp. 342-369) to assess poll accuracy, I analyze poll estimates from
these 23 polling organizations.

Four of these polls appear to have overestimated McCain
support (indicated with a * below), while most polls (17) overestimated Obama strength.
Pre-election projections for two organizations’ final polls—Rasmussen and Pew—were
perfectly in agreement with the actual election result (**).
The following list ranks the 23 organizations by the accuracy of their final, national preelection
polls (as reported on pollster.com).

1. Rasmussen (11/1-3)**
1. Pew (10/29-11/1)**
2. YouGov/Polimetrix (10/18-11/1)
3. Harris Interactive (10/20-27)
4. GWU (Lake/Tarrance) (11/2-3)*
5. Diageo/Hotline (10/31-11/2)*
5. ARG (10/25-27)*
6. CNN (10/30-11/1)
6. Ipsos/McClatchy (10/30-11/1)
7. DailyKos.com (D)/Research 2000 (11/1-3)
8. AP/Yahoo/KN (10/17-27)
9. Democracy Corps (D) (10/30-11/2)
10. FOX (11/1-2)
11. Economist/YouGov (10/25-27)
12. IBD/TIPP (11/1-3)
13. NBC/WSJ (11/1-2)
14. ABC/Post (10/30-11/2)
15. Marist College (11/3)
16. CBS (10/31-11/2)
17. Gallup (10/31-11/2)
18. Reuters/ C-SPAN/ Zogby (10/31-11/3)
19. CBS/Times (10/25-29)
20. Newsweek (10/22-23)
poll accuracy in the 2008 presidential election.pdf application/pdf Object.

Costas Panagopoulos, Ph.D.
Department of Political Science
Fordham University
For inquiries: cpanagopoulo@fordham.edu or (917) 405-9069

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