Presidential Polls 2012: CNN Poll Shows Statistical Tie, But It is Completely Skewed Toward Obama


I was inspired to look beyond the topline of CNN's November 4 presidential poll that showed the candidates tied, because I had already determined that it would be pretty difficult for President Obama to be genuinely tied with Mitt Romney nationwide. 

Polls with no skin in the swing state game showed the president was down 1.6 to 1.8 million votes between 2008 and now in the non-swing state of California, and where would that large number of votes come from outside of coastal blue state strongholds? 

CNN's most recent poll has an astounding D+11 sample (41 Democrat 30 Republican 29 Independent), which, depending upon how you view these matters, is either extreme wishful thinking or a sampling from another country and voting population entirely.

The CNN article, methodology, and survey differ in their margins of error. The article says the poll has a 3.5% MOE, the survey document, 3.0% for the toplines, and the crosstabs have a stunning 8.5% MOE. I am pretty sure I could do better than 8.5% going door to door with a clipboard and ballpoint pen.

Given the Washington Post's exit poll history, there was a D+3 advantage in 2006, and a documented (US Census) D+7 advantage during the Democrats' high water mark in 2008. This sampling isn't just as if 2010 never happened, it's more like 1944. However, it's not 1944, and we are not fighting the Nazis.

Has CNN been consistent in its poll weighting? The October 1 poll, which showed President Obama up over Romney by 3 points, 50 to 47%, used the following breakdown: 37 Democrat, 29 Republican, and 34 Independent, for a total of D+8. D+8 is CNN's exit poll statistic from the 2008 election. 

The September 9 post-convention CNN poll does not contain any information about its methodology. So, to determine that the Presidential race is tied, CNN was required to increase its already inflated sample of Democrats by 3 points to an historic high of 35% more than 2008, and decrease its sample of Independents by 5 points, or 40% fewer than voted in 2008, and knock Republicans back to Goldwater-era levels. Well done, CNN.

Unless something astonishing happens tomorrow, the CNN polls may go down as the least reliable from a major news organization in history.