This, from Megan McArdle:
My assertion that there’s a 70% chance that the GOP controls White House, Senate, and House in 2017 has attracted a lot of pushback. And it’s certainly possible that I’m wrong! Here’s my thinking, for what it’s worth: Since the Civil War, only two Democratic presidents have been succeeded by another Democrat. Both of them–FDR and JFK–accomplished this by dying in office. Since World War II, only four presidents have been succeeded by a member of their party. As I mentioned above, two of them accomplished this by dying in office. One of them accomplished this by resigning in disgrace ahead of his own impeachment. Only one of them, Ronald Reagan, left office at the end of his appointed term and was succeeded by a duly elected member of his own party.
reminds me of this classic cartoon by XKCD, which should be blown up into A0 format, and placed in a permanently visible position in front of the desk of every pundit tempted to make pseudo-quantitative oracular announcements about American politics (extremists might want to go the full Clockwork Orange with the eyeclamps but that strikes me as overkill).
Human beings are cognitively predisposed to perceive patterns in the world. Many, likely most of these patterns are garbage. Without good theories, and good ways of testing those theories, we’ll never be able to tell the garbage patterns from the real ones.