*Last update: Thu Jun 5 14:57:39 2008*

## Recent electability | ||

## Lifetime electability (30-day moving average) | ||

## How electable are the candidates for our next president? That is, if they were nominated, what chance would they have of being elected?Prediction
markets give us a way to estimate the probability of certain
events. For example, the Iowa
Electronic Markets offer a contract which will pay out at $1 if the
Republican nominee receives more popular votes than the Democrat, and
$0 otherwise. The market price of this contract can be seen as an
estimate of the probability that the Republican nominee wins more of the
popular vote. Intrade has
similar contracts for each individual candidate. Historically, these
markets have been more
accurate predictors than polls. However, to the best of my
knowledge, none of the markets measure But we can infer electability fairly easily. Using conditional probabilities, Pr[elected] = Pr[elected | nominated] · Pr[nominated] + Pr[elected | not nominated] · Pr[not nominated]. We can fairly safely assume that Pr[elected | not nominated] = 0 (which did not hold for Joe Lieberman, but that wasn't a presidential election). Thus, we are left with Pr[elected] = Pr[elected | nominated] · Pr[nominated], so electability can be estimated as Pr[elected] / Pr[nominated]. Intrade has contracts which can be used to estimate those two probabilities for the major candidates, and makes historical daily closing prices conveniently available. The plots above show estimated electability as a function of time,
updated daily. Interestingly, [as of February 2007] neither party's frontrunner is the most
electable candidate for their party. Among the Republicans, McCain and
Romney are fairly consistently bested by Giuliani. Among the Democrats,
Hillary Clinton is historically the What can we make of Obama's stellar 90% electability or Giuliani's 85% in October 2006? Well, in short, if you think that was a poor prediction, then you missed an opportunity to earn some money by purchasing the appropriate contracts at Intrade---either betting that their nomination was more likely, or that their chance of winning the election was less likely. --Brighten Godfrey - 2007.02.11 |
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## Pr[nominated] (30-day moving average) | ||

## Pr[elected] (30-day moving average) | ||