What is the probability that there will be a decisive state with a very close vote total?
Nate Silver says there is (as of Oct. 3) a 4% chance that a recount will be required; that is, that a decisive state will have a margin within 0.5%. There are about 8 swing states, so the odds that any one (let’s say Florida) would require a recount is about 1/8 of 4% or 0.5%. There are 6 million voters in Florida, so a recount occurs there when the vote totals are within 30,000 of each other. So there’s about a 1/30,000 chance that the recount will end up so even that your vote would decide it. All together that’s a one in 6 million chance that your vote (assuming you live in one of the 8 swing states) would decide the election. Andrew Gelman of Columbia University computes similar odds: one in 10 million if you live in NM, NH, VA, or CO, one in 20 million if you live in NV, and so on. If you live in a solid state like Oklahoma or California, your vote will not be decisive.
