NESN's Twitter question of the day in the first game of the Sox/Rays doubleheader was introduced by Jenny Dell, who said something to the effect of how it's generally accepted that sweeping a doubleheader is rare, and asked Twitter: "Why is it so hard to sweep a doubleheader?" This has been argued in the past by baseball writers - in 2009 Joe Morgan said in an ESPN column, "...in the history of baseball 80% of all doubleheaders have been split."
I'll tell you right now that Joe Morgan is way off, and NESN is starting from a false assumption as well. I replied to their twitter question, we'll see if it makes the broadcast. I'm sure it won't.
But my question is, what is the probability that a doubleheader is swept? What is the probability that YOUR TEAM sweeps a doubleheader? And does anyone else know how those probabilities compare to the historical rates of doubleheader sweepage?