Do we know what % of voters switched party support in each election?

[Mr. Morden]

Is there any way besides exit polls alone to estimate how many people voted for one party's presidential nominee in one election, and then the opposing party's nominee in the following election?  I realize that the exit polls purportedly tell us who people voted for in the previous election, but people often lie both about whether they voted last time and who they voted for.  So I was wondering if anyone has ever tried to use turnout data and precinct level results, or something like that, to give some supporting evidence re: this question?

Reason I'm wondering is because I'll be curious to see if we get a larger than normal number of crossover votes this time because Trump is such an unusual candidate, and I'm wondering if the only thing we'll be able to use for evidence is the exit poll question.  Maybe some combination of the "Who did you vote for last time?" question and other demographic info in the exit poll might shed some light on it?  I mean, if there's a huge swing in the educational subsamples, then presumably some of that is because of people switching from one party to another rather than because of a different group of people showing up at the polls.

Of course, if we're getting more than 5% of voters going 3rd party this time, that skews it further.  There could be plenty of people who don't switch from one major party to the other but instead switch from one of the major parties to 3rd party.

[Mr. Morden]

Take this with a grain of salt, since I don't remember which poll measured this, but I recall reading in 2012 that for every two Obama 08 voters that he lost, Obama gained one McCain voter.

Well, in most years they ask on the exit poll "Who did you vote for in the last election?", so supposedly we know the answer.  But as I said, not everyone tells the truth about whether they voted last time and who they voted for.

However, I just looked up the 2012 exit poll, and didn't see the "Who did you vote for last time?" question in there at all.  Is it there, but I missed it?  Because it's something they've asked in every other GE exit poll since at least the 90s, so it would be weird if they dropped it in 2012.

[Mr. Morden]

I looked at yesterday's exit poll, and didn't even see a question about who people voted for in 2012.  Is it in there, but I missed it?  Very disappointing if they didn't ask this, as I was quite curious to have some indication of how many Obama and Romney voters swapped parties this time.