Arizona CNN Debate

Shortly after the debate ended, mainstream media exploded with their “expert” opinions on who won the debate.  Most outlets claimed that Mitt Romney won the debate with his combative style that he adopted in the two debates in Florida last month.  We demonstrated with data that this style did indeed help Romney in the Florida debates, but how did his strategy fair in last night’s debate?  Did he actually win the debate?

The graph below shows Intrade price fluctuations during the debate.  An increase in the price indicates that the probability of the candidate winning the presidency increased while the opposite is true for a decrease in price. 

Notice that Mitt Romney had the largest increase in his Intrade price.  His probability of winning the presidency increased by 2% as a result of his performance in last night’s debate.  On the surface it appears his strategy worked again.

Newt Gingrich had no net change in his price during the debate indicating that Intrade users felt that his debate performance had a neutral effect on his chances of winning the presidency.

Ron Paul had a very slight decrease in his Intrade price.  This was most likely not due to a poor debate performance, but was probably due to changes in other candidates prices.

Rick Santorum’s Intrade price plummeted in the debate.  His debate performance decreased his probability of winning the presidency by 1.2%.   

One interesting thing to note is that Barack Obama’s Intrade price increased during the debate.  This is highly interesting considering Intrade fluctuations from February 1st to February 19th.  Note, also, that Barack Obama’s performance isn’t typically analyzed in debates he did not participate in by many media outlets.  But people’s perceptions of how likely he is to become president are always fluctuating based on events such as these debates.  Please take note of the graph below.  The left vertical axis (primary axis) shows Mitt Romney and Barack Obama’s Intrade prices.  The right vertical axis (secondary axis) shows Rick Santorum’s Intrade price.  Santorum was given a secondary axis to better illustrate his surge.

Notice that when Rick Santorum surges on Intrade (and the polls) Barack Obama’s probability of winning the presidency increases while Mitt Romney’s probability decreases.  This shows that Intrade users believe that Romney has a better chance of winning against Barack Obama relative to Rick Santorum.  This is interesting because last night’s data seems to contradict this correlation. 

So how can an increase in Romney’s price occur simultaneously with an increase in Obama’s price?  Some reasons we can think of include:

1)      Romney’s approach last night was over the top, and though it might have helped his chances of winning the nomination, it hurt the Republican Party’s chances of winning the general election.

2)      Intrade users now feel Rick Santorum has a better chance at beating Obama relative to Romney.

3)      Some other variable caused Barack Obama’s price to increase during the debate.

We don’t know causality but can certainly identify the correlations.  You decide the causality.

Learn more about big data and politics at

Share this article