Shown immediately below is the electoral map depicting the results of the 2008 presidential election in which Barack Obama won with 365 electoral votes to John McCain's 173. Below, the Intrade results are shown. Further down you will find the 2008 pollster report card.Obama 365
Shown immediately below is the Nov 4, 2008 election day forecast from the Intrade prediction market. Intrade did not predict Nebraska splitting its votes, and it was the first time in state history that this happened. Missouri and Indiana were also reversed in the forecast, but both having eleven electoral votes resulted in a nearly dead-on electoral vote count.Obama 364
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.
|NBC News / Wall St. Journal||76%||C||77%||75%|
|ABC News / Wash Post||67%||D+||62%||82%|
|CBS News / NYT||60%||D-||62%||56%|
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|
|NBC News / Wall St. Journal||51||43||8||1.5|
|ABC News / Wash Post||53||44||9||2.5|
|CBS News / NYT||51||42||9||2.5|
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 )
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