Baseball Prospectus Glossary
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A player's True Average minus batting average. Provides a quick picture on whether a player's batting average is "empty" or "full."
True Average (TAv) is a measure of total offensive value scaled to batting average. Adjustments are made for park and league quality, as such the league-average mark is constant at .260.
True Average incorporates aspects that other linear weights-based metrics ignore. Reaching base on an error and situational hitting are included; meanwhile, strikeouts and bunts are treated as slightly more and less damaging outs than normal. The baseline for an average player is not meant to portray what a typical player has done, but rather what a typical player would do if given similar opportunities. That means adjustments made for parks and league quality. True Average's adjustments go beyond applying a blanket modifier-players who play more home games than road games will see that reflected in their adjustments. Unlike its predecessor, Equivalent Average, True Average does not consider baserunning or basestealing.
Here is an example of the True Average spectrum based upon the 2009-2011 seasons:
Excellent - Miguel Cabrera .342
Great - Alex Rodriguez .300
Average - Austin Jackson .260
Poor - Ronny Cedeno .228
Horrendous - Brandon Wood .192
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See: http://www.baseballprospectus.com/article.php?articleid=11717
0.9 (from the article) is no longer a stationary number, but a scale based on current season runs. It's all the way up to almost 1.07 now, due to run scoring being so much lower than when Colin wrote this (from the link above):
From 1993 to 2009, you can figure TAv simply as:
0.260 + (RAA/PA)*.9
Now, we will be tuning those values slightly to match the batting average for that season, but other than
that, that’s the formula for TAv we will be using once the new stat reports are rolled out.
[...]
All that matters essentially is the computation of the initial R/PA values. When people ask about wOBA, most
of the time what they really care about is the values presented on Fangraphs, derived from this set of
linear weights developed by Tom Tango.
True Average Against is to True Average what Batting Average Against is to Batting Average. In other words, True Average Against will tell you how well opposing batters have hit a pitcher. Do note that while True Average Against takes the pitcher's park, league, and situational-based hitting into account, it does not exclude data where the pitcher faced an opposing pitcher. Because of that, National League pitchers should possess lower True Average Against than their American League counterparts.
Total bases - A home run is 4 total bases, a triple is 3, a double is 2, and a single is 1. Walks, steals, sacrifices, and other non-hit advancement do not count as a total base.
Total batters faced.
Not recorded for the NL 1876-1886, the AA of 1882-83, the 1884 UA, or the NA of 1871-75.
Total Base Percentage -- total bases per plate appearance (as opposed to slugging average, SLG, which is total bases per at-bat)
Total days lost to injury.
Number of days the team has lost to injuries for the season.
Team.
As used in most places (including the PECOTA cards), Team is the three letter abbreviation for a major league, minor league, or foreign team.
Number of ties
Tommy John Surgery
Team.
The team that is at bat (1=home, 0=away)
Times On Base -- times reaching base by hit, walk, or hit by pitch. Reaching by error is sometimes included, depending on the context.
A player's total defensive value - the sum of his FRAA and POS_ADJ.
Total number of pitches thrown as a starter.
Total Pitcher Abuse Points (PAP) accumulated
Triple plays
TRAA - Takeoff Rate Above Average - is the official name for Stolen Base Attempts Above Average. Please click here for details: Takeoff Rate Above Average
The model for TRAA (Takeoff Rate Above Average) is similar to SRAA, but more complicated. With Takeoff Rate, we don't care whether the baserunner actually succeeds in stealing the base; what we care about is that he made an attempt.
(from http://bbp.cx/a/26195)
Our hypothesis is that base-stealing attempts are connected with the pitcher’s ability to hold runners. When baserunners are not afraid of a pitcher, they will take more steps off the bag. Baserunners who are further off the bag are more likely to beat a force out, more likely to break up a double play if they can’t beat a force out, and more likely to take the extra base if the batter gets a hit.
Takeoff Rate stats consider the following factors:
- The inning in which the base-stealing attempt was made;
- The run difference between the two teams at the time;
- The stadium where the game takes place;
- The underlying quality of the pitcher, as measured by Jonathan Judge’s cFIP statistic;
- The SRAA of the lead runner;
- The number of runners on base;
- The number of outs in the inning;
- The pitcher involved;
- The batter involved;
- The catcher involved;
- The identity of the hitter on deck;
- Whether the pitcher started the game or is a reliever.
Takeoff Rate Above Average is also scaled to zero, and negative numbers are once again better for the pitcher than positive numbers. By TRAA, here were the pitchers who worried baserunners the most in 2014.
And here were the pitchers who emboldened baserunners in 2014:
Three True Outcomes -- home runs, walks, and strikeouts. Expressed as a rate stat, the formula is TTO% = ((HR+BB+SO) / PA) * 100%
Originally conceived of as an offbeat tribute to Rob Deer (http://www.baseballprospectus.com/article.php?articleid=724), the TTO celebrates batters who don't put the ball into play.
Ironically, TTO gained some credence beyond it's novelty value with the development of Voros McCracken's DIPS theory that states that pitchers have little control over the outcomes of batted balls in play, and thus should be evaluated primarily on the basis of the strikeouts, walks, and home runs they allow.
BP has awarded the TTO crown annually for several years. e.g. http://www.baseballprospectus.com/article.php?articleid=4721
Type of team streak (Winning or Losing)
Translated at-bats: number of at-bats adjusted for park and season.
Translated batting average: batting average adjusted for park and season. Equal to T_H / T_AB.
Translated doubles: number of doubles adjusted for park and season.
Translated triples: number of triples adjusted for park and season.
Translated walks: number of walks adjusted for park and season.
Translated caught stealing: number of times caught stealing adjusted for park and season.
Translated hits: number of hits adjusted for park and season.
Translated hit by pitch: number of times hit by pitch adjusted for park and season.
Translated home runs: number of home runs adjusted for park and season.
Translated OBP: on-base percentage adjusted for park and season.
Translated outs: number of outs made (AB-H+CS+SH+SF) adjusted for park and season.
Translated runs: number of runs scored adjusted for park and season.
Translated RBI: number of runs batted in adjusted for park and season.
Translated stolen bases: number of stolen bases adjusted for park and season.
Translated SLG: slugging percentage adjusted for park and season.
Translated strikeouts: number of strikeouts adjusted for park and season.
Team's expected winning percentage in games started by a pitcher
The Team Audit Standings provide a portal on how teams are performing in general categories.
Rather than concern itself with a team's playoff odds or underlying indicators, the Team Audit Standings page focuses on the fundamentals: a team's record, how many games the team trials in the division, runs scored and allowed per game, the per game run differential, how a team stacks up against its Pythagorean record, and each team's Hit List rank.
An adjustment made for hitters, to account for not having to face their own pitchers. Using pitching stats, (league R * pf - team R), divided by (league IP - team IP), divided by park-adjusted league runs per inning.
An adjustment made for pitchers, to account for not having to face their own team's batters. Using batting stats, (league runs * pf - team runs), divided by (league PA - team PA), divided by league runs per plate appearance * pf.
Team's expected losses in the games started by the pitcher. This will always add (with TmW) up to the pitcher's total games started.
Team's expected wins in the games started by the pitcher. This will always add (with TmL) up to the pitcher's total games started.
Team's expected winning percentage in the games started by the pitcher.
Total WARP (Wins Above Replacement) as listed on his PECOTA card, considering both a player's offensive and defensive contributions. See WARP1.
Hits plus doubles plus two times triples plus three times home runs.
The total number of baserunners that have been on base for a batter's plate appearances.
Whether a player is listed as day-to-day or went on the 15-day or 60-day disabled list due to the injury.
The Transactions Browser was designed to serve as a portal to all the latest transaction news and analysis.
Converts the player's batting statistics into a context that is the same for everybody. The major characteristics of the translation are: 1) that the translated EQA should equal the original, all-time adjusted EQA (within some margin for error); 2) that all seasons are expanded to a 162 game schedule; 3) that the statistics are adjusted to a season where an average hitter would have, per 650 PA: 589 AB, 153 H, 31 DB, 3 TP, 19 HR, 56 BB, 5 HBP, 113 SO, 10 SB, 5 CS, 79 R and 75 RBI. His rates would be a .260 batting average, .330 onbase average, .420 slugging average, and a .260 EQA with 76 EQR.
Converts all pitching statistics into a standard context. Pitchers are translated to a league where the top five pitchers (in innings) pitch an average of 275 innings. An average pitcher will have rates, per nine innings, of 9.00 hits, 1.00 home run, 3.00 walks, 6.00 strikeouts, and 4.50 earned runs. In the standard context, a replacement level pitcher has a 6.00; the translation is set up to conserve runs above replacement (alltime PRAR). Wins and losses are set using the pythagorean formula with average run support, with the pitcher's actual deviation from his real expected win percentage added back in.
Trend identifies players who demonstrate dramatic changes from their Baseline during their comparable year. For Hitters: Hitters who improve their EqR/PA by at least 20% are identified by a green, upward-pointing arrow and contribute to a hitter's Breakout score; hitters whose EqR/PA decreases by at least 20% are identified by a red, downward-pointing arrow and contribute to a hitter's Collapse score. For Pitchers: Pitchers who improve their EqERA by at least 20% are identified by a green, upward-pointing arrow and contribute to a pitcher's Breakout score; pitchers whose EqERA increases by at least 25% are identified by a red, downward-pointing arrow and contribute to a pitcher's Collapse score.
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