From SABR members Rob Arthur and Greg Matthews at FiveThirtyEight on August 11, 2017:
We’ve all seen a pitcher when he’s zeroed in: His mechanics are clean, his curveball is dropping off the table and he’s painting the edge of the zone. But just as often, a hurler can lose command, and we see pitches that normally look sharp getting hammered into the stands. These streaks are confounding; for no apparent reason, a journeyman can look like a Hall of Famer, or a Cy Young winner can look like an ordinary junkballer.
Sabermetricians usually insist that such streaky performances are really just an artifact of fans and journalists forcing narratives onto random patterns. No matter how much it seems like a pitcher is getting hot, the more likely explanation is that they just happen to have bunched a few good innings together. But that’s not quite correct: Using a new method that focuses on fastball velocity, we found a way to detect whether a pitcher is actually throwing with a hot hand — and just how big of a difference it can make.
Arguments over streakiness in baseball are almost as old as the sabermetric movement itself, and for a long time, research seemed to disprove the notion of a “hot hand” effect or argue that it played only a severely limited role. But although the sabermetric community felt certain that these streaks were just coincidence, nearly every baseball player insists that hot streaks are real.
Read the full article here: https://fivethirtyeight.com/features/baseballs-hot-hand-is-real/
Originally published: August 11, 2017. Last Updated: August 11, 2017.