I'm looking for the title and author of a book.
I believe the action takes place in XXth century's USA, in an alternative history. Statistical and political analyses made huge progresses, to the point that they can forecast with a 100% accuracy the result of upcoming elections. A president is about to be elected, and their analysis show that the result of the election will actually be decided by a single man. They start looking for this man, to ask him to vote, and, actually, to decide who will be the next president.
Does that ring a bell? I'm sorry if the plot I described is vague, I never read that book, just remember hearing someone mention it.