tRA is a baseball statistic used to measure the performance of a

pitcher In baseball, the pitcher is the player who throws ("Pitch (baseball), pitches") the Baseball (ball), baseball from the pitcher's mound toward the catcher to begin each play, with the goal of out (baseball), retiring a batter (baseball), batter, ...

. Similar to FIP, tRA uses a mathematical formula to isolate the pitcher from his defense. Thus, tRA is a defense-independent pitching statistic. Unlike FIP and dERA, however, tRA takes into account

batted ball In the sports of baseball and softball, a batted ball is a Pitch (baseball), pitch that has been contacted by the batter's bat. Batted balls are either fair ball, fair or foul ball, foul, and can be characterized as a fly ball, pop-up, line driv ...

type (that is, line drives, fly balls, pop ups, and ground balls) as well as strikeouts, walks, and home runs.

Theory and method

tRA was developed by Graham MacAree. According to StatCorner, "The batter may strike out looking, strike out swinging, walk, be walked intentionally or be hit by a pitch. The hitter may also hit a line drive, a ground ball, an outfield fly, a popup, a bunt or a home run. These possibilities can be regarded as being governed by the pitcher, provided that there is a large enough sample size. tRA is built around knowing how many runs and outs each of these events are worth." tRA uses play-by-play data gathered from each

MLB Major League Baseball (MLB) is a professional baseball league composed of 30 teams, divided equally between the National League (baseball), National League (NL) and the American League (AL), with 29 in the United States and 1 in Canada. MLB i ...

season in order to give each possible outcome between a pitcher and a batter a linear weight. For example, in 2008, a line drive went for an out 30.5% of the time, while it had a run value of 0.384. These statistics are used to calculate expected outs (xOuts) and expected runs (xRuns). Once these values are obtained, tRA can be converted to runs per nine innings by taking (xRuns/xOuts)*27. Like other

sabermetrics Sabermetrics (originally SABRmetrics) is the original or blanket term for sports analytics in the US, the empirical analysis of baseball, especially the development of advanced metrics based on baseball statistics that measure in-game activity ...

, tRA has alternate versions. tRA+ is compared to league average. For example, a tRA+ of 120 would mean that pitcher was 20% better than league average. tERA is tRA except that it is scaled to

earned run In baseball, an earned run is any run that was fully enabled by the offensive team's production in the face of competent play from the defensive team. Conversely, an unearned run is a run that would not have been scored without the aid of an erro ...

s allowed instead of runs allowed.

References

{{DEFAULTSORT:TRA (baseball statistic)

tRA Tra or TRA may refer to: Biology * TRA (gene), in humans encodes the protein T-cell receptor alpha locus * Tra (gene), in ''Drosophila melanogaster'' encodes the protein female-specific protein transformer * Tra gene, a transfer gene * Triple rel ...