Baseball Baselining: How Likely Is a Comeback?

Monday night, my wife posed a baseball question I couldn’t immediately answer. As the Angels and Giants went to the eighth inning with the Halos up by a run, she had a simple question: How often does a team that’s losing after seven innings come back and win? I guess I could have gone to our wonderful WPA Inquirer, a fun little tool for hypotheticals. That tells me that the Giants had around a 25% chance to win heading into the eighth. But I took her question as a broader one, concerned not just with that specific game, but with all games. How likely is a comeback?
I didn’t know the answer offhand, and I couldn’t find it on Google either (secret professional writer tip: use Google). So I did what anyone in my situation would do: I said “I don’t know, but now I’m going to write an article about this.” Two days later, here we are.
I’m hardly the first person to do research on comebacks. Russell Carleton has been looking into comebacks for a while. Rob Mains has too. Chet Gutwein investigated comeback wins and blown saves here at FanGraphs in 2021. Everyone loves to write about comebacks. Baseball Reference even keeps a list of the biggest comeback wins. They’re memorable games, and fertile ground for investigation. Read the rest of this entry »