"Our elections are like Three-Card Monte: What you see is not what you get."

Obama’s projected base case (60% UVA) vote share is V=53.52%. Assuming a 2.0% polling MoE, his popular vote win probability is 99.97%:
99.97% = NORMDIST (.5352, .50, .02/1.96, true). Assuming a 3.0% MoE, the probability is 98.94%.

The National Model calculates the moving average projection based on the latest 5 national polls. The base case 60% UVA scenario is assumed. The normal distribution function calculates win probabilities using the average 5-poll average MoE. The latest 5 national polls have an average 2.70% MoE. Based on the 51.88% moving average projection, there is a 91.38% probability that Obama will win the popular vote:
91.38% = NORMDIST (.5188, .50, .027/1.96, true)

The win probability in each state is also calculated by the normal distribution applied to the projection. A 4% poll margin of error is assumed. Obama leads McCain in Florida by 49-47%. Based on his 51.4% projected share, there is a 75.4% probability that he will win the state:
75.4% = NORMDIST (.514, .50, .04/1.96, true)