in Ben and I's tour of the rules changes in the minors today, one of the things that stuck out most to me is that the robo-umps in the minors are occassionally making huge mistake calls--often balls on pitches right down the middle. theringer.com/mlb/2021/10/21… of course, human umps screw up these calls too, but what we found is that the robots are messing up on 99.9% strike calls about twice as often as humans are, which is surprising and potentially a significant barrier to their implementation at the MLB level.

The Dodgers had the highest spin rate in the league by a mile ever since signing Trevor Bauer. Since mid-May when players stopped using sticky stuff, they've also lost the most spin of any team.🤔baseballprospectus.com/news/article/6… The team that used to have the highest spin rate by a wide margin? The 2020 Cincinnati Reds. Since Bauer left, they dropped ~150 RPM.

4chan's evolution into an engine of bigotry and far-right content was driven in part by a secretive site administrator (with the charming handle of "RapeApe") who pushed the moderator corps towards allowing more racist and toxic content. Me, @motherboard vice.com/en/article/m7a… For those who don't know, 4chan is an extremely rare combination on the internet of 1) a very popular website, with ~20M visitors a month and 2) a festering cesspool of hate, with more hate speech than openly Neo Nazi domains, and an incredible amount of threats of violence, etc.

Using the data on trash can bangs assembled by @adams_at, I took a look at how the Astros did when they were receiving signals. Short answer: the banging alone doesn't seem to have helped them. Long answer: it all depends on whether the signal was accurate baseballprospectus.com/news/article/5… @adams_at Overall, the banging signal was about 93% accurate in predicting a non-fastball (very good). And when the bang was right, hitters added ~25 points to their SLG, also very good and a significant benefit when summed up over the entire team.

MLB's report from yesterday finally explains why we got a rocket ball the last few years: lower seam height. There are a ton of interesting findings in there that I break down in this article: baseballprospectus.com/news/article/5… The committee had to build new equipment and testing procedures to detect the difference in seam height from year to year, which is almost infinitesimal at *one-thousandth of an inch*. For reference, that's about the width of a single human skin cell.

The Astros' trash can banging/sign stealing system left a clear signature in the audio data, which I then used to track when/how they were doing it. baseballprospectus.com/news/article/5… A couple of interesting things: one, they started the sign-stealing almost immediately in each game, usually by the fourth or fifth pitch or so. Also, they were very accurate, like maybe suspiciously so--they never seemed to make a mistake.

Rising costs to attend baseball games explain about 40% of the 5 million person decrease in attendance since 2015. baseballprospectus.com/news/article/5… A sad finding in this article is that the effect of rising ticket prices doesn't reduce attendance enough to offset the additional revenue they get from charging their remaining fanbase more $$$.

Did they dejuice the baseball? Did they rejuice the baseball? The answer is both, depending on the day. MLB seems to have very little control over the baseball's performance: sometimes it's the rocket ball, sometimes it's lead by comparison. baseballprospectus.com/news/article/5… Every day the ball fluctuates over a huge range of drag coefficients, and I found there's a direct connection between that fluctuation and how the ball performs that day (in terms of home run probability and fly ball distance).

Air resistance in the playoffs has shot up to the highest level since 2016, causing fewer homers. Multiple lines of evidence suggest that the postseason baseball is totally different than the one used in the regular season. baseballprospectus.com/news/article/5… This is data coming from MLB's own pitch tracking system, and I confirmed it by looking at how many homers you would expect to see based on exit velocity+launch angle+park effects. There have been about *50%* fewer home runs than expected.