Wednesday, September 19, 2012

Who is the best Pollster? Check it out...

With all the doom and gloom on how Governor Romney is doing, it is nice to see the new Rasmussen poll... with Romney up and ahead of Obama... but what is even nicer, is to see how credible the Rasmussen polling organization is... check out the "report card" below.   You gotta love it!

2008 Pollster Report Card

The table below is an assessment of pollster performance in the 2008 Presidential election.  The pollsters were graded on both the accuracy of their final poll (popular vote) and the consistency of their polling during the month of October.
The overall score is a weighted average of their Accuracy and Consistency numbers.  The weighting is 75% accuracy and 25% consistency.  Formula details are at the bottom of this page.
  Overall        
Poll Score Grade   Accuracy Consistency
Rasmussen Reports 91% A-   92% 86%
Ipsos/McClatchy 89% B+   92% 79%
CNN/Opinion Research 88% B+   92% 77%
Fox News 84% B   92% 61%
Pew 83% B-   92% 56%
GWU/Battleground 79% C+   92% 41%
Diageo/Hotline 77% C+   77% 79%
NBC News / Wall St. Journal 76% C   77% 75%
Gallup Traditional 73% C-   77% 63%
Marist 67% D+   62% 82%
ABC News / Wash Post 67% D+   62% 82%
IBD/TIPP 66% D   77% 34%
Gallup Expanded 66% D   62% 78%
CBS News / NYT 60% D-   62% 56%
Reuters/C-SPAN/Zogby 35% F   31% 48%
Data
The data for this chart come from the  Real Clear Politics summary on 12 November 2008.   Here is a local mirror of that data, with the final polls summarized at the top.  Here is a quick summary of the final spread predicted by the pollsters, ranked from most accurate to least:
Poll Obama McCain   Spread (actual=6.5)   Off by
Rasmussen Reports 52 46   6   0.5
Pew 52 46   6   0.5
GWU/Battleground 50 44   6   0.5
Ipsos/McClatchy 53 46   7   0.5
CNN/Opinion Research 53 46   7   0.5
Fox News 50 43   7   0.5
Diageo/Hotline 50 45   5   1.5
NBC News / Wall St. Journal 51 43   8   1.5
Gallup Traditional 51 43   8   1.5
IBD/TIPP 52 44   8   1.5
Marist 52 43   9   2.5
ABC News / Wash Post 53 44   9   2.5
Gallup Expanded 52 43   9   2.5
CBS News / NYT 51 42   9   2.5
Reuters/C-SPAN/Zogby 54 43   11   4.5

Formulas
Every final poll showed Obama with a lead, so assessing their accuracy is just a matter of comparing their forecasted spread with the actual spread of the election which was Obama +6.5.  
Final poll accuracy score =  100 -  (  |(POLL SPREAD - 6.5)| / 6.5  )
All the pollsters graded had more than one poll during the month of October.  If a poll reported a wide spread and then suddenly narrowed down right before the election, this formula produces a lower score.  Likewise a pollster gets a lower score if they predicted a very tight race until the end and then widened up.
October Consistency = 100 - ( POLL STDEV / POLL AVERAGE )

2 comments:

Anonymous said...

Tide's a turnin'...Obama's got it in the bag!

God bless.

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