Gruber: Rethinking the win curve

From Max Gruber at The Hardball Times on November 21, 2017, with mention of SABR President Vince Gennaro:

Transaction analysis has become one of the most important topics in all of baseball research. The primary tool that is used in almost all public transaction analysis is a dollars/WAR calculation. This tool has been convenient in many applications. It is especially good for predicting how much money an upcoming free agent will receive on the open market.

However, dollars/WAR also has significant limitations. In many situations, it simply does answer the questions we are interested in. As an example, let’s look at the Chris Sale trade to the Chicago White Sox. Last offseason, the White Sox traded Sale to the Red Sox in exchange for Yoan Moncada, Michael Kopech, Luis Alexander Basabe and Victor Diaz.

By a dollars/WAR calculation, this was pretty close to an even trade, seeming to be mutually beneficial. The Red Sox preferred the present wins in the form of a starting pitcher, and the White Sox preferred the prospects. A dollars/WAR calculation does not allow us to see how much each team benefitted from this deal. I will present a new framework that can help teams make decisions under uncertainty. We will be able to see how much any player is worth to any team given a team’s preferences and the player’s impact on the team’s projections.

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Originally published: November 21, 2017. Last Updated: November 21, 2017.