Glossary:
Looking to find a definition fast? Use the quick find button
, located in the top right hand corner. NB: All averages presented are MLB league averages.
BABIP (League average for starting pitcher (SP): .297, for relief pitcher (RP): .290, for hitters: roughly LD + 0.11)
The percentage of balls in play (batted balls minus homeruns) that go for a hit.
The percentage of balls in play (batted balls minus homeruns) that go for a hit.
Ball% (SP/RP: 36.5%)
The percentage of pitches thrown that are called a ball. The R2 of Ball% to walks is roughly +.56 on a cubic formula.
The percentage of pitches thrown that are called a ball. The R2 of Ball% to walks is roughly +.56 on a cubic formula.
Btd% (SP: 20.2%, RP: 18.5%)
The percentage of pitches thrown that are swung at, contacted, and kept in fair territory. This is *not* balls in play, Batted% includes pitches hit for home runs.
The percentage of pitches thrown that are swung at, contacted, and kept in fair territory. This is *not* balls in play, Batted% includes pitches hit for home runs.
BB% (SP: 8%, RP: 9.5%)
The percentage of plate appearances that result in a walk. Expressing by % of plate appearances is more appropriate than by game or by nine innings.
The percentage of plate appearances that result in a walk. Expressing by % of plate appearances is more appropriate than by game or by nine innings.
bRAA
Stands for batting runs above average. It is computed by taking the hitter's RV/PA and multiplying by the number of plate appearances he has had that season.
Stands for batting runs above average. It is computed by taking the hitter's RV/PA and multiplying by the number of plate appearances he has had that season.
ClStr% (SP: 17.1%, RP: 16.1%)
The percentage of pitches thrown that are taken by the hitter and called a strike. Interestingly enough, the R2 of ClStr% to strikeouts is only +.006 suggesting little relationship between the two.
The percentage of pitches thrown that are taken by the hitter and called a strike. Interestingly enough, the R2 of ClStr% to strikeouts is only +.006 suggesting little relationship between the two.
Ct% (Hitters: 81.5%)
The percentage of pitches a batter swings at that he connects on, including foul balls.
The percentage of pitches a batter swings at that he connects on, including foul balls.
Fl% (Hitters: 47%)
The percentage of pitches a batter swings and connects on that he hits foul. E.g. Number of fouls / Number of contacts.
The percentage of pitches a batter swings and connects on that he hits foul. E.g. Number of fouls / Number of contacts.
Foul% (SP: 17.5%, RP: 17.8%)
The percentage of pitches thrown that are swung on and fouled off. E.g. Number of fouls / Number of pitches.
The percentage of pitches thrown that are swung on and fouled off. E.g. Number of fouls / Number of pitches.
GB% (SP/RP: 43.2%)
The percentage of batted balls that are hit on the ground as determined by MLB.com.
The percentage of batted balls that are hit on the ground as determined by MLB.com.
HBP% (SP/RP: 0.95%)
The percentage of batters faced that are hit by a pitch. When talking about a pitcher's control a good measure to use is to combine HBP% along with uBB% to represent the percentage of batters that a pitcher unintentionally put on base due to wildness.
The percentage of batters faced that are hit by a pitch. When talking about a pitcher's control a good measure to use is to combine HBP% along with uBB% to represent the percentage of batters that a pitcher unintentionally put on base due to wildness.
HR/BIA (SP: 6.5%, RP: 6.0%)
The percentage of balls in the air (line drives + flyballs + pop ups) that go for a homerun. Balls in Air is used as a denominator to avoid confusion between exactly what constitutes a flyball versus a line drive or pop up amongst different scorers.
The percentage of balls in the air (line drives + flyballs + pop ups) that go for a homerun. Balls in Air is used as a denominator to avoid confusion between exactly what constitutes a flyball versus a line drive or pop up amongst different scorers.
iBall% (SP: 0.4%, RP: 1.2%)
The percentage of pitches thrown intentionally for a ball. This includes balls as part of intentional walks and also pitchouts.
The percentage of pitches thrown intentionally for a ball. This includes balls as part of intentional walks and also pitchouts.
InP% (Hitters: 53%)
The percentage of pitches a batter swings and connects on that he hits fair. E.g. Number of fair balls / Number of contacts.
The percentage of pitches a batter swings and connects on that he hits fair. E.g. Number of fair balls / Number of contacts.
LD% (SP/RP: 18.9%)
The percentage of batted balls that are hit for a line drive as determined by MLB.com.
The percentage of batted balls that are hit for a line drive as determined by MLB.com.
lgTRA
Represents the average tRA based on the pitcher's league (AL vs NL) and role (SP vs RP). Seperating by role eliminates the pesky problem of correcting for RP having better core stats than SP and seperating by league eliminates the problem of possible league skill differences.
Represents the average tRA based on the pitcher's league (AL vs NL) and role (SP vs RP). Seperating by role eliminates the pesky problem of correcting for RP having better core stats than SP and seperating by league eliminates the problem of possible league skill differences.
LOB%(SP: 70.7%, RP: 72.8%)
Per Hardball Times LOB% is used to track pitcher's luck or effectiveness (depending on your point of view). The exact formula is (H+BB+HBP-R)/(H+BB+HBP-(1.4*HR)).
Per Hardball Times LOB% is used to track pitcher's luck or effectiveness (depending on your point of view). The exact formula is (H+BB+HBP-R)/(H+BB+HBP-(1.4*HR)).
Mis% (Hitters: 18.5%)
The percentage of pitches a batter swings at that he misses, e.g. Number of misses / Number of swings.
The percentage of pitches a batter swings at that he misses, e.g. Number of misses / Number of swings.
O-xO
More detail is given in the tRA primer but O-xO represents the difference between the actual number of outs (O) recorded by a pitcher and the expected number of outs (xO). A positive number means that more outs than expected have been recorded, suggesting good luck, good defense or a helpful park while a negative number means that fewer outs than expected have been recorded, suggesting possible bad luck, bad defense or a hitter friendly park.
More detail is given in the tRA primer but O-xO represents the difference between the actual number of outs (O) recorded by a pitcher and the expected number of outs (xO). A positive number means that more outs than expected have been recorded, suggesting good luck, good defense or a helpful park while a negative number means that fewer outs than expected have been recorded, suggesting possible bad luck, bad defense or a hitter friendly park.
pRAA
Stands for pitching runs above average. Using tRA as the benchmark, the formula is (lgTRA * xOuts / 27) - xRuns.
Stands for pitching runs above average. Using tRA as the benchmark, the formula is (lgTRA * xOuts / 27) - xRuns.
Pull% (Hitters: 58%)
The percentage of batted balls that are pulled, defined by hitting to the same side of a line extending toward center field from home plate that the hitter bats from. E.g. balls hit to the right of said line by left-handed batters and vice versa are considered pulled.
The percentage of batted balls that are pulled, defined by hitting to the same side of a line extending toward center field from home plate that the hitter bats from. E.g. balls hit to the right of said line by left-handed batters and vice versa are considered pulled.
RV/PA
As decribed by Tom Tango here. "Run value per PA above average = (wOBA for player - wOBA for league) / 1.15."
As decribed by Tom Tango here. "Run value per PA above average = (wOBA for player - wOBA for league) / 1.15."
RV600
Stands for runs above average per 600 plate appearances. It is the hitter's RV/PA multiplied by 600. 600 was chosen because it represents roughly a full season of projected time.
Stands for runs above average per 600 plate appearances. It is the hitter's RV/PA multiplied by 600. 600 was chosen because it represents roughly a full season of projected time.
Sac
Sacrifice bunts only since those are the only type of sacrifices that deduct from plate appearances when computing on base percentage.
Sacrifice bunts only since those are the only type of sacrifices that deduct from plate appearances when computing on base percentage.
SwStr% (SP: 7.8%, RP: 9.5%)
The percentage of pitches thrown that are swung on and missed. These have a direct linear relationship with a pitcher's strikeout rate and are often a good leading variable for how a pitcher will perform in the future.
The percentage of pitches thrown that are swung on and missed. These have a direct linear relationship with a pitcher's strikeout rate and are often a good leading variable for how a pitcher will perform in the future.
TkB% (Hitters: 68.8%)
The percentage of pitches that a batter takes that are called a ball. This is the inverse of TkS%
The percentage of pitches that a batter takes that are called a ball. This is the inverse of TkS%
TkS% (Hitters: 31.2%)
The percentage of pitches that a batter takes that are called a strike. This is the inverse of TkB%.
The percentage of pitches that a batter takes that are called a strike. This is the inverse of TkB%.
tRA
Developed by Graham MacAree, the basic introduction to tRA is located here. tRA involves assigning run and out values to all events under a pitcher's control and coming up with an expected number of runs allowed and outs generated in a defense and park neutral environment. tRA is on a R/9 scale and does not involve any regression of the rates so while it should be more useful at determining a pitcher's true talent level, the best method for pitching projection is to use tRA*, the regressed version of tRA.
Developed by Graham MacAree, the basic introduction to tRA is located here. tRA involves assigning run and out values to all events under a pitcher's control and coming up with an expected number of runs allowed and outs generated in a defense and park neutral environment. tRA is on a R/9 scale and does not involve any regression of the rates so while it should be more useful at determining a pitcher's true talent level, the best method for pitching projection is to use tRA*, the regressed version of tRA.
tRA*
The regressed version of tRA. tRA* takes each of the pitcher's major component stats and regresses them back to league average, the magnitude of regression being based on the amount of batters the pitcher faces. tRA* is not a measurement of a pitcher's results per se, but should be seen as the system's best estimate of a pitcher's true talent level based on his stats in any given year at any given level. tRA* does not consider a pitcher's statistics from other years and leagues.
The regressed version of tRA. tRA* takes each of the pitcher's major component stats and regresses them back to league average, the magnitude of regression being based on the amount of batters the pitcher faces. tRA* is not a measurement of a pitcher's results per se, but should be seen as the system's best estimate of a pitcher's true talent level based on his stats in any given year at any given level. tRA* does not consider a pitcher's statistics from other years and leagues.
tRA+
Like wOBA+. tRA+ is equal to [((lgTRA - tRA) / lgTRA) + 1] * 100. This formula puts tRA+ on the same scale as wOBA+. A tRA+ of 150 represents that the pitcher's tRA was 50% better than league average. A tRA+ of 75 means the pitcher's tRA was 25% worse than average.
Like wOBA+. tRA+ is equal to [((lgTRA - tRA) / lgTRA) + 1] * 100. This formula puts tRA+ on the same scale as wOBA+. A tRA+ of 150 represents that the pitcher's tRA was 50% better than league average. A tRA+ of 75 means the pitcher's tRA was 25% worse than average.
wOBA
wOBA or weighted on base average is a statistic developed by and used with the permission of Tom Tango. He gives a detailed rundown of it here. In a nutshell, wOBA uses linear weights on certain batting events to come up with a metric that is more statistically sound than OPS and is scaled onto an OBP scale. According to Tango "An average hitter is around 0.340 or so, a great hitter is 0.400 or higher, and a poor hitter would be under 0.300."
wOBA or weighted on base average is a statistic developed by and used with the permission of Tom Tango. He gives a detailed rundown of it here. In a nutshell, wOBA uses linear weights on certain batting events to come up with a metric that is more statistically sound than OPS and is scaled onto an OBP scale. According to Tango "An average hitter is around 0.340 or so, a great hitter is 0.400 or higher, and a poor hitter would be under 0.300."
wOBA+
Like OPS+, wOBA+ is a percentage better or worse than league average with 100 representing average. wOBA+ is equal to wOBA* / lgWOBA * 100.
Like OPS+, wOBA+ is a percentage better or worse than league average with 100 representing average. wOBA+ is equal to wOBA* / lgWOBA * 100.
xOuts
More detail is given in the tRA primer but xOuts stands for the expected number of outs a pitcher has generated based on his defense and park neutral outcomes.
More detail is given in the tRA primer but xOuts stands for the expected number of outs a pitcher has generated based on his defense and park neutral outcomes.
xR-R
More detail is given in the tRA primer but xR-R represents the difference between the expected number of runs (xR) recorded by a pitcher and the actual number of runs (R). A positive number means that less runs than expected have scored, suggesting good luck, good defense or a helpful park while a negative number means that more runs than expected have been score, suggesting possible bad luck, bad defense or a hitter friendly park.
More detail is given in the tRA primer but xR-R represents the difference between the expected number of runs (xR) recorded by a pitcher and the actual number of runs (R). A positive number means that less runs than expected have scored, suggesting good luck, good defense or a helpful park while a negative number means that more runs than expected have been score, suggesting possible bad luck, bad defense or a hitter friendly park.
xRuns
More detail is given in the tRA primer but xRuns stands for the expected number of runs a pitcher has yielded based on his defense and park neutral outcomes.
More detail is given in the tRA primer but xRuns stands for the expected number of runs a pitcher has yielded based on his defense and park neutral outcomes.
© 2009 StatCorner