Posted by Dan Hirsch on October 21, 2020
Last month, we added Championship Leverage Index (cLI) and Championship Win Probability Added (cWPA) to Baseball-Reference. These stats measure how much of an impact each player had on their team's chances of winning the World Series. Today, we are launching the Pivotal Play Finder, which measures the impact that each individual play had on a team's World Series win probability. This tool allows you to customize your query using a number of different filters to find the most impactful plays in a given situation.
It's not surprising to see that the most pivotal play in MLB history occurred in Game 7 of the 1960 World Series. But many would be shocked to find out that it was not Bill Mazeroski's walk-off (which is 6th all-time). The most pivotal play actually occurred an inning earlier. In the bottom of the 8th inning with 2 outs, the Pirates were down 7-6 with runners on the corners when Hal Smith put his team up by two runs with a 3-run home run. This play increased the Pirates' chances of winning the World Series from 30% to 93%. Unfortunately for Smith, the Yankees erased the lead in the top of the 9th, and then Mazeroski became the hero.
With the Pivotal Play Finder, you can search by event type and find out that Babe Ruth's caught stealing to end the 1926 World Series was the most impactful caught stealing in MLB history (10.22%), or that Fred Snodgrass' muff in the 1912 World Series was the most critical error in history (24.39%).
We can also search for plays involving a particular player. Derek Jeter was involved in many memorable moments during his career, but none more pivotal than his walk-off home run in Game 4 of the 2001 World Series.
In addition to sorting by Championship Win Probability Added, we can also sort by Championship Leverage Index to find the most crucial moments. These situations are usually the most pressure-packed because the difference between an out and a run has an enormous impact on a team's World Series win probability. The situation with the highest cLI in MLB history came in Game 7 of the 1962 World Series. In the bottom of the 9th inning, the Giants were down 1-0 with 2 outs and runners on 2nd and 3rd with Willie McCovey at the plate. A hit would likely tie or win the game (and World Series) for the Giants, while an out would mean a championship for the Yankees. As we know, McCovey lined out sharply to Bobby Richardson to end the series.
Please note that at the time of this writing, Regular Season event data is complete back to 1973, mostly complete back to 1950, and somewhat complete back to 1916. Postseason event data is complete back to 1903. Please see the data coverage page for details.