Prediction Markets Update (September 12, 2008)

As of 4:40 p.m. Central time today, the McCain Intrade contract (2008.PRES.McCAIN) is trading at 51.5, which is 1 point up from yesterday’s close of 50.5, whereas the Obama Intrade contract (2008.PRES.OBAMA) is trading at 48, which is .4 points down from yesterday’s close of 48.4.

Examining the state-by-state contracts, I find that by using a cutoff price point of 55 for allocating Electoral College votes, that this currently gives Barack Obama 264 Electoral College votes and John McCain 265 Electoral College votes. Basically, the story today on a state-by-state is the same as it was yesterday; out of the 102 total contracts (Democratic and Republican) offered (for the 50 states and the District of Columbia), only the two Colorado contracts (COLORADO.DEM and COLORADO.REP) remain within my arbitrarily defined “swing state” price interval, since the last trades on these contracts were 52 and 48 respectively.

I like to compare the prediction market data with Nate Silver’s PECOTA model which is published on the FiveThirtyEight website. Today (for the first time), Mr. Silver’s model has McCain winning the Electoral vote by a margin of 277 to 261.

Addendum: September 12, 2008 Electoral College Vote allocation

John McCain (265): Alabama (9), Alaska (3), Arizona (10), Arkansas (6), Florida (27), Georgia (15), Idaho (4), Indiana (11), Kansas (6), Kentucky (8), Louisiana (9), Mississippi (6), Missouri (11), Montana (3), Nebraska (5), Nevada (5), North Carolina (15), North Dakota (3), Ohio (20), Oklahoma (7), South Carolina (8), South Dakota (3), Tennessee (11), Texas (34), Utah (5), Virginia (13), West Virginia (5), and Wyoming (3)

Barack Obama (264): California (55), Connecticut (7), Delaware (3), District of Columbia (3), Hawaii (4), Illinois (21), Iowa (7), Maine (4), Maryland (10), Massachusetts (12), Michigan (17), Minnesota (10), New Hampshire (4), New Jersey (15), New Mexico (5), New York (31), Oregon (7), Pennsylvania (21), Rhode Island (4), Vermont (3), Washington (11), and Wisconsin (10)

Print Friendly, PDF & Email

Leave a Reply