Every pitch is assigned a run value based on its outcome (ball, strike, home run, etc.). The sum of all of a player's contributions across a season, or multiple seasons, measures his overall batting or pitching run value. A positive value represents runs created for hitters, and runs prevented for pitchers.
Statcast calculates two versions of batting and pitching run value: context-neutral and leveraged.
Context-neutral run value excludes the impact of the base/out situation on the play -- i.e. it does not matter whether the play happens with no outs and the bases empty, or two outs and the bases loaded. This is the primary version of batting and pitching run value currently displayed on Baseball Savant, allowing for a more standardized comparison of players' hitting or pitching performances.
Leveraged run value weights the impact of a play based on the base/out situation -- in a higher-leverage situation, the positive or negative run value resulting from a pitch will be greater. Hitters and pitchers who have better "clutch" performances might have higher total run values using the leveraged version. This leaderboard also includes how much extra run value a player gains or loses from his performance in different leveraged situations.
