Stolen Thunder: 11/04/2012

Monday, November 05, 2012

An Alternative To Nate Silver: Here Are The Real Odds

Back in 2008, a man who established his reputation with Baseball statistics was lionized as a political guru for correctly “predicting” the winner of 49 of the 50 states. He did this through aggregation of state polls, and a formula which, speaking bluntly, was based heavily on subjective weighting of polls he liked. On his side, it’s true Silver was accurate in 2008. Silver, however, doesn’t like anyone bringing up his results in the 2010 mid-term election. This year, Silver has announced that President Obama has an almost ninety percent chance of winning re-election. He has also, rather dishonestly, tried to hedge his predictions by saying that turnout will decide the actual odds (hidden well below his bold headline), and admitted that if the state polls used invalid weighting on party participation, then the election results may be very different from his forecast. His supporters have even gone so far in recent days as to demand that Silver’s system be judged on the process rather than whether his predictions come true. Leaving all this aside, the question may reasonably be asked, about what the odds really are for Obama and Romney. There is a reasonable method available for determining those odds.

Whenever a percentage chance is given for something happening, it claims that of a hundred possible outcomes, this one will happen ‘x’ number of times. So we can figure up the odds by working out what each candidate needs, and how they could get there.

First, President Obama. By this date, there’s really no doubt that the District of Columbia and the following states will be won by Obama: California, Connecticut, Delaware, Hawaii, Illinois, most of Maine, Maryland, Massachusetts, New Jersey, New York, Rhode Island, Vermont, and Washington. That gives Obama DC plus 13 states, for 178 Electoral Votes, meaning he needs another 92 EV to win re-election.

Next, Governor Romney. There is no doubt that Romney will win the following states: Alabama, Alaska, Arizona, Arkansas, Florida, Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, West Virginia, and Wyoming. That gives Romney 24 states for 220 Electoral Votes, meaning he needs another 50 EV to win the White House.

There are 13 battleground states plus 1 EV in Maine that is contested, for 140 Electoral Votes. From the start we can see that neither candidate needs to sweep all the battleground states to win.

Before going on, there is a controversy which will sort itself out tomorrow. Many state polls have given heavy advantage in weighting to Democrats, even when previous elections show no such disparity in voting by party. As a result, there is suspicion among conservatives that the state polls are inaccurate in stating actual voter support. So the question comes down to whether turnout will be like 2008, 2004, or somewhere in between. For each of the states, therefore, we can look at the actual part weights from 2004 and 2008, then use that to tell us what we might see this year. Here’s how each state plays out, starting with the highest EV states still contested:

Pennsylvania: 20 EV, polls either even or show Obama slightly ahead