Each play in the playoffs holds extra weight compared to the regular season. An error can change a game, and a loss can doom a series. In close games and series, it is often the team that executes the small plays that comes out on top.

A particular play in Game 2 of the NLDS between Washington and Los Angeles stood out in this context: Asdrúbal Cabrera singled to right field, driving in Ryan Zimmerman. However, the throw from the outfield held up Kurt Suzuki at third base, and Cabrera was thrown out trying to advance to second base on the throw. Although the Nationals still won the game, the baserunning error was not inconsequential in the series.

Evaluating the Result with WE and RE24

Two statistics – Win Expectancy and RE24 – can be used to show why trying to advance was a bad decision.

Win expectancy (WE) is the probability a team will win given the specific circumstances. Greg Stoll’s Win Expectancy Calculator [1] shows how potential baserunning outcomes by Cabrera change Washington’s win expectancy in Table 1 below.

The Nationals’ win expectancy before Cabrera’s single was 82.7%. The highest WE is 93.4% and results when Cabrera gets to second base, however, staying at first only decreases Washington’s win expectancy by 0.9%. In comparison, getting thrown out decreases their chances by 6.7% compared to staying at first. A 0.9% increase in WE is probably not worth risking 6.7%, especially in a playoff game where you have the lead. Read the rest of this entry »