Statcast OAA Is Now Available on FanGraphs

The MLB Statcast fielding metric Outs Above Average (OAA) is now available on player pages in the “Advanced Fielding” section and on the leaderboards. We’ve also included the accompanying Fielding Runs Prevented metric (RAA), which is OAA converted to runs above average.

From MLB.com’s Statcast glossary:

Outs Above Average for outfielders starts with Catch Probability, which takes the distance an outfielder must go, the time he has to get there, and the direction he travels to put a percentage of catch likelihood on each individual batted ball. OAA for outfielders is the season-long cumulative expression of each individual Catch Probability play. For example, if an outfielder has a ball hit to him with a 75 percent Catch Probability — that is, one an average outfielder would make three-quarters of the time — and he catches it, he’ll receive a +.25 credit. If he misses it, he’ll receive -.75, reflecting the likelihood of that ball being caught by other outfielders.

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Outs Above Average for infielders takes the following factors into account.

• How far the fielder has to go to reach the ball (“the intercept point”).
• How much time he has to get there.
• How far he then is from the base the runner is heading to.
• On force plays, how fast the batter is, on average. (A runner’s average Sprint Speed is used in the calculation, rather than his Sprint Speed on that particular play. For new players with no data, a league-average — 27 ft/sec — score is used; once the player qualifies for the leaderboard, all of his previous plays are re-run.)

You can read more about Outs Above Average here, Fielding Runs Prevented here, with further details available on Baseball Savant.