What is this? A Statcast metric designed to express the overall value of a baserunner, measured in runs created (or lost) via stealing bases and taking extra bases on the basepaths.
How this works: Each steal opportunity is assigned a probability of being successful or not based on several inputs, including the speed of the runner and his lead distance. Each successful or failed steal attempt is assigned a run value, with a stolen base or advance via a balk worth +0.2 runs for the baserunner and a caught stealing or pickoff worth -0.45 runs.
For non-steal baserunning plays, an estimated success probability is generated for each opportunity using inputs that include runner speed, outfielder throwing arm, runner position on the basepaths and outfielder distance from both the ball and the bases. That can be translated to a run value based on whether the runner successfully takes the extra base, is thrown out or does not attempt to advance (holds).
How to read it: Baserunning Run Value is a combination of both categories of baserunning -- stolen bases and extra bases taken -- into one overall value number.
For example: "Trea Turner has been the most valuable baserunner in MLB in the Statcast era, with a Baserunning Run Value of +55 runs created from 2016-24. Turner has 28 runs created via stolen bases and 27 runs created via extra bases taken."
