# Information Theory and the U.S Election, from Steve Ellison

November 3, 2008 |

Why waste time watching election returns when you could be improving yourself or spending time with your family? According to Claude Shannon's information theory, the information content of news is proportional to how unexpected the news is. Hence, Obama carrying California or McCain carrying Alabama would have near-zero information content because these events are already expected with near-certainty.

Using the Intrade state prediction markets, the five states with the highest degree of uncertainty in the Presidential election are:

Missouri:        Obama p=0.55  McCain p=0.45
Indiana:         Obama p=0.40  McCain p=0.60
North Carolina:  Obama p=0.67  McCain p=0.33
North Dakota:    Obama p=0.29  McCain p=0.71
Montana:         Obama p=0.28  McCain p=0.72

Hence, the results in these states will be highly newsworthy. However, their newsworthiness is likely to be limited to establishing Obama's exact margin of victory, since there are 26 states and the District of Columbia with a total of 338 electoral votes in which Obama's probability of victory is at least 0.75.

A McCain upset would be more newsworthy, since it would be unexpected. To win, McCain would not only have to win all of the above states, but also win 70 of the 100 electoral votes available in these seven states in which his probability of victory is between 0.10 and 0.25.

New Mexico (5):     McCain p=0.10
Virginia (13):      McCain p=0.10
Pennsylvania (21):  McCain p=0.11
Colorado (9):       McCain p=0.12
Nevada (5):         McCain p=0.14
Ohio (20):          McCain p=0.19
Florida (27):       McCain p=0.24

To narrow the focus even further, Virginia, Ohio, Pennsylvania, and most of Florida are in the Eastern time zone. If Obama wins at least two of those four states, it's over.

## Nigel Davies writes:

Reminds me of the story about the Hungarian Grandmaster Lajos Portisch, who was at home studying chess as the Soviet tanks rolled into Budapest. I supposed he decided that there wasn't much he could do about the tanks.

Portisch would later become Hungary's top player and was for many years one of the top players in the world. He's the closest thing in Budapest to royalty.

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