KEY:
BP - comes from Baseball Prospectus
BS - comes from Baseball Statistics
FG - comes from FanGraphs
IN - comes from Best Forex Trading Software
THT - comes from The Hardball Times
Adjusted for all-time - BP
Statistics that have been adjusted for all-time have all of the adjustments for a single season, plus two more. One adjustment normalizes the average fielding numbers over time. Historically, the fielding share of total defense has been diminishing with time - more walks, more strikeouts, and more home runs means less work for fielders. In the single-season adjustments, fielders from before WWII have a lot more value than fielders today; the all-time adjustments have attempted to remove that temporal trend. The second adjustment is for league difficulty. You better record a game on tv right on your dvd-r and watch it later after reading this so you'd understand what I'm saying. League quality has generally increased with time in contrast to fear of driving which reduces with time. Each league has been rated for difficulty and compared to a trend line defined by the post-integration National League. In addition to the adjustments for season, an adjustment is made for league difficulty.
Adjusted for season - BP
Statistics that have been adjusted for a single season are the best stats to use when you are only interested in that one season. In these, adjustments have been made to account for the home park and for the offensive level of the league as a whole. Hitters have an adjustment for not having to face their own team’s pitchers because of home loan bad credit problems; pitchers have a similar adjustment for not having to face their own hitters. Hitters in the AL since 1973 have a disadvantage in these statistics, since the league average is artificially inflated by the use of the DH and no adjustment is made for that.
BABIP - BP
Batting Average on balls put into play. A pitcher’s average on batted balls ending a plate appearance, excluding home runs. Based on the research of Voros McCracken and others, BABIP is mostly a function of a pitcher’s defense and luck, rather than persistent skill. Thus, pitchers with abnormally high or low BABIPs are good bets to see their performances regress to the mean. A typical BABIP is about .290.
Batting Runs - BS
The Linear Weights measure for how many runs a hitter contributes above and beyond what a league average replacement player would provide. Converts a number of offensive statistics into their run equivalent, based on Pete Palmer’s 1978 computer simulation of major league games since 1901. The formula is:
Runs = (.47) 1B + (.78) 2B + 1.09 (3B) + (1.40) HR + .33 (BB+HBP)
- .25 (AB-H) - (0.50) (Outs on base)
BIZ - THT
Balls in Zone, a fielding stat that represents the total number of balls that were batted into a fielder’s zone while he was in the field.
BLOB - BP
Batters left on base
BR9 - BP
Baserunners per 9 innings. BR = (H+BB+HBP)/IP*9
BRAA - BP
Batting Runs Above Average. The number of runs better than a hitter with a .260 EQA (i.e., an average hitter) and the same number of outs; EQR - 5 * OUT * .260^2.5.
BRAP - BP
Batting Runs Above Replacement. The number of runs better than a hitter with a .230 EQA and the same number of outs; EQR - 5 * OUT * .230^2.5.
BRARP - BP
Batting runs above a replacement at the same position. A replacement position player is one with an EQA equal to (230/260) times the average EqA for that position.
Clutch - THT
“Clutch” is the name given to the portion of Bill James’s Runs Created formula that includes the impact of a batter’s batting average with runners in scoring position and the number of home runs with runners on. The specific formula is Hits with RISP minus overall BA times at bats with RISP, plus HR with runners on minus (all HR/AB) times at bats with runners on. This stat is not a definitive description of “clutch hitting,” just one way of looking at it.
Clutchiness - FG
Clutchiness = WPA (OPS Wins*pLI)
DERA - BP
Defense-adjusted ERA. Not to be confused with Voros McCracken’s Defense-Neutral ERA. Based on the PRAA, DERA is intended to be a defense-independent version of the NRA. As with that statistic, 4.50 is average. Note that if DERA is higher than NRA, you can safely assume he pitched in front of an above-average defense.
EqA - BP
Equivalent Average. A measure of total offensive value per out, with corrections for league offensive level, home park, and team pitching. EQA considers batting as well as baserunning, but not the value of a position player’s defense. The EqA adjusted for all-time also has a correction for league difficulty. The scale is deliberately set to approximate that of batting average. League average EqA is always equal to .260. EqA is derived from Raw EqA, which is (H + TB + 1.5*(BB + HBP + SB) + SH + SF) divided by (AB + BB + HBP + SH + SF + CS + SB). REqA is then normalized to account for league difficulty and scale to create EqA.
EqBA - BP
EqBA, or Equivalent Batting Average, is calibrated to an ideal major league with an overall EqBA of .270. While a major league hitter’s equivalent stats should not differ substantially from his actual numbers, a minor league hitter’s equivalent stats undergo translation and may differ significantly. Equivalent stats also account for park effects.
EqERA - BP
EqERA is calibrated to an ideal major league where EqERA = 4.50. While a major league pitcher’s equivalent stats should not differ substantially from his actual numbers, a minor league pitcher’s equivalent stats undergo translation and may differ significantly. Equivalent stats also adjust for park effects, and the quality of a pitcher’s defense. EqERA is conceptually identical to NRA, as used in the DT cards.
EqR - BP
Equivalent Runs; EQR = 5 * OUT * EQA^2.5. In the fielding charts, the estimated number of EqR he had at the plate while playing this position in the field. In Adjusted Standings, EqR refers to the total number of equivalent runs scored by the team.
ERA+ - THT
ERA measured against the league average, and adjusted for ballpark factors. An ERA+ over 100 is better than average, less than 100 is below average.
Expected Win Shares - THT
Expected Win Shares are a playing time metric. They are the number of Win Shares a player would be expected to accumulate, given his playing time (including plate appearances, innining in the field, and innings pitched), if he were an average player. Expected Win Shares is a baseline for evaluating Win Shares totals, as in Win Shares Above Bench.
FB% - BP
Percentage of batted balls that were classified as fly balls (percentage is based on the number of batted balls that were classified at all — batted balls which do not have a known type are omitted)
Fielding Wins - BS
Fielding Runs divided by the number of runs required to create an additional win beyond average. That average is defined as a team record of .500 because a league won-lost average must be .500.
FIP - THT
Fielding Independent Pitching, a measure of all those things for which a pitcher is specifically responsible. The formula is (HR*13+(BB+HBP)*3-K*2)/IP, plus a league-specific factor (usually around 3.2) to round out the number to an equivalent ERA number. FIP helps you understand how well a pitcher pitched, regardless of how well his fielders fielded. FIP was invented by Tangotiger.
FRAA - BP
Fielding Runs Above Average.
FRAR - BP
Fielding Runs Above Replacement. The difference between an average player and a replacement player is determined by the number of plays that position is called on to make. That makes the value at each position variable over time. In the all-time adjustments, an average catcher is set to 39 runs above replacement per 162 games, first base to 10, second to 29, third to 22, short to 33, center field to 24, left and right to 14.
GB% - BP
Percentage of batted balls that were classified as ground balls (percentage is based on the number of batted balls that were classified at all — batted balls which do not have a known type are omitted)
GPA - THT
Gross Production Average, a variation of OPS, but more accurate and easier to interpret. The exact formula is (OBP*1.8+SLG)/4, adjusted for ballpark factor. The scale of GPA is similar to BA: .200 is lousy, .265 is around average and .300 is a star. A simple formula for converting GPA to runs is PA*1.356*(GPA^1.77).
ISO - BP
Isolated Power (ISO) is one of five primary production metrics used in identifying a hitter or pitcher’s comparables. PECOTA uses a slightly modified version of Isolated Power that assigns the same value to triples as to doubles (extending a double into a triple is generally an indicator of speed, rather than additional power). Thus, the formula for isolated power as follows: ISO = (2B + 3B + HR*3) / AB
LD% - THT
Line Drive Percentage. Baseball Info Solutions tracks the trajectory of each batted ball and categorizes it as a groundball, fly ball or line drive. LD% is the percent of batted balls that are line drives. Line drives are not necessarily the hardest hit balls, but they do fall for a hit around 75% of the time.
Leverage Index - THT
Leverage Index, invented by Tangotiger, is a measure of how critical a specific batting situation is. One (1) is average, anything above one is more critical and anything less than 1 is less critical. Baseball Prospectus has its own definition of Leverage Index, but Tangotiger’s (who originated the term) definition is better and more accurate.
MLV - BP
Marginal Lineup Value, a measure of offensive production created by David Tate and further developed by Keith Woolner. MLV is an estimate of the additional number of runs a given player will contribute to a lineup that otherwise consists of average offensive performers.
MLVr - BP
MLVr is a rate-based version of Marginal Lineup Value (MLV), a measure of offensive production created by David Tate and further developed by Keith Woolner. MLV is an estimate of the additional number of runs a given player will contribute to a lineup that otherwise consists of average offensive performers. MLVr is approximately equal to MLV per game. The league average MLVr is zero (0.000). Additional information on MLV and MLVr can be found here.
OBI% - BP
Others Batted In Percentage — the fraction of runners on base who were driven in during a batter’s plate appearances. OBI is distinguished from RBI (runs batted in) in that OBI does not credit the batter for his own scoring on a home run. In otherwords OBI = RBI - HR
OBP - THT
On-base percentage. (H + BB + HBP) divided by (AB + BB + HBP + SF). For pitchers, OBP is on base percentage allowed.
OPS - THT
On Base Percentage + Slugging Percentage
OPS+ - THT
OPS measured against the league average, and adjusted for ballpark factors. An OPS+ over 100 is better than average, less than 100 is below average.
OWP - BP
Offensive Winning Percentage. A Bill James stat, usually derived from runs created. In EqA terms, it could be calculated as (EQA/refEQA)^5, where refEQA is some reference EQA, such as league average (always .260) or the position-averaged EQA.
Park Factor - BS
Calculated separately for batters and pitchers. Above 100 signifies a park favorable to hitters; below 100 signifies a park favorable to pitchers.
STATS uses a five-year average Park Factor for players and teams unless they change home parks. They first compute a Park Index, which is the ratio of runs scored (both by and against a particular team) in the home ballpark to the runs scored (by and against) in visiting ballparks.
Once an index has been created, adjustments are made to reflect the fact that a team plays fewer innings at home than on the road - the home team doesn’t bat in the bottom of the ninth if it is leading - and to reflect the fact that the team being rated doesn’t get to play road games in its own park. For example, the Colorado Rockies play in Coors Field, a ballpark which boosts run production. Their Park Index is going to be very high, because far more runs are scored at home than on the road. However, every other team in the league gets to play some road games at Coors, benefiting from it’s friendliness to hitters; the Rockies must play every road game away from Coors, and that dilutes their Park Factor.
PECOTA - BP
Stands for Player Empirical Comparison and Optimization Test Algorithm. PECOTA is BP’s proprietary system that projects player performance based on comparison with thousands of historical player-seasons. Analyzes similarities with past player-seasons based not only on rate statistics, but also height, weight, age, and many other factors.
pLI - FG
Average Leverage Index per plate appearance. Average runs percentage index per third at-bat correlation groundout ratio of runs average.
PR - THT
Invented by John Thorn and Pete Palmer, this is a measure of the number of runs a pitcher saved compared to average. The formula is league-average RA/IP minus park-adjusted RA/IP, times total innings pitched. This is the same formula as Lee Sinins’ RSAA.
PRAA - BP
Pitcher-only runs above average. The difference between this and RAA is that RAA is really a total defense statistic, and PRAA tries to isolate the pitching component from the fielding portion. It relies on the pitching/fielding breakdown being run for the team, league, and individual. The individual pitching + defense total is compared to a league average pitcher + team average defense, and the difference is win-adjusted.
PRAR - BP
Pitcher-only runs above replacement. Similar to PRAA, except that the comparison is made to a replacement level player instead of average. The nominal RA for a replacement pitcher is 6.11 (the same ratio, compared to a 4.50 average, as a .230 EQA is to .260). This assumes that there is a 50/50 split between pitching and fielding. If the pitch/field split is less than that, as it was in the 1800s, the replacement ERA is reduced.
Pythagenport - BP
A modified form of Bill James’ pythagorean formula. Instead of using a fixed exponent (2, 1.83), the “pythagenport” formula derives the exponent from the run environment - the more runs per game, the higher the exponent. The formula for the exponent was X = .45 + 1.5 * log10 ((rs+ra)/g), and then winning percentage is calculated as (rs^x)/(rs^x + ra^x). The formula has been tested for run environments between 4 and 40 runs per game, but breaks down below 4 rpg.
After further review, I (Clay) have come to the conclusion that the so-called Smyth/Patriot method, aka Pythagenpat, is a better fit. In that, X=((rs+ra)/g)^.285, although there is some wiggle room for disagreement in the exponent. Anyway, that equation is simpler, more elegant, and gets the better answer over a wider range of runs scored than Pythagenport, including the mandatory value of 1 at 1 rpg.
Pythagorean Record - THT
A formula for converting a team’s Run Differential into a projected Won/Loss record. The formula is RS^2/(RS^2+RA^2). Teams’ actual won/loss records tend to mirror their Pythagorean records, and variances can usually be attributed to luck.
You can improve the accuracy of the Pythagorean formula by using a different exponent (the 2 in the formula). In particular, a sabermetrician named US Patriot discovered that the best exponent can be calculated this way: (RS/G+RA/G)^.285, where RS/G is Runs Scored per game and RA/G is Runs Allowed per game. This is called the PythagoPat formula.
RAA - BP
For Pitchers:
Runs above average. At its simplest, this would be the league runs per inning, times individual innings, minus individual runs allowed. However, we have gone one step beyond that, because being 50 runs above average in 1930, in the Baker Bowl, doesn’t have the same win impact as being +50 in the 1968 Astrodome. The league runs per inning need to be adjusted for park and team hitting (and difficulty, for the alltime RAA), and then you can multiply by individual innings and subtract individual runs. Finally, that quantity needs to be win-adjusted. See win-adjustment.
For Fielders:
Runs above average at this position, similar to Palmer’s Fielding Runs as far as interpretation is concerned.
Range Factor - THT
A measure of the total chances fielded in a player’s playing time. The formula is 9*(PO+A)/Innings in Field.
RAP - BP
Runs Above Position: The number of Equivalent Runs this player produced, above what an average player at the same postion would have produced in the same number of outs.
RAR - BP
Runs Above Replacement. RAR compares a hitter’s Equivalent Run total to that of a replacement level player who makes the same number of outs and plays the same position. A replacement level player is one who has .736 times as many EqR as the average for that position; that corresponds to a .351 winning percentage.
RC - THT
Runs Created. Invented by Bill James, RC is a very good measure of the number of runs a batter truly contributed to his team’s offense. The basic formula for RC is OBP*TB, but it has evolved into over fourteen different versions. We use the most complicated version, which includes the impact of hitting well with runners in scoring position, and is adjusted for ballpark impact. RC/G refers to Runs Created Per Game, which Runs Created divided by the number of outs made by the batter, times 27.
RCAA - THT
Runs Created Above Average. A stat invented and tracked by Lee Sinins, the author of the Sabermetric Baseball Encyclopedia. Lee calculates each player’s Runs Created, and then compares it to the league average, given that player’s number of plate appearances.
REqA - BP
Raw equivalent average, the first step towards building the EqA. In its fullest form, REQA = (H + TB + 1.5*(BB + HBP + SB) + SH + SF) divided by (AB + BB + HBP + SH + SF + CS + SB). REQA gets converted into unadjusted equivalent runs, UEQR.
RZR - THT
Revised Zone Rating is the proportion of balls hit into a fielder’s zone that he successfully converted into an out. Zone Rating was invented by John Dewan when he was CEO of Stats Inc. John is now the owner of Baseball Info Solutions, where he has revised the original Zone Rating calculation so that it now lists balls handled out of the zone (OOZ) separately (and doesn’t include them in the ZR calculation) and doesn’t give players extra credit for double plays (Stats had already made that change). To get a full picture of a player’s range, you should evaluate both his Revised Zone Rating and his plays made out of zone (OOZ).
SLG
Slugging percentage (hitters) or slugging percentage allowed (pitchers). Total bases divided by at-bats.
TB - THT
Total Bases, calculated as 1B+2B*2+3B*3+HR*4.
Total Average - BS
Tom Boswell’s formulation for offensive contribution from a variety of batting and baserunning events. The concept of the numerator is bases gained, that of the denominator is outs made:
(Total Bases + Steals + Walks + HBP - Caught Stealing)
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(At-Bats - Hits + Caught Stealing + GIDP)
VORP - BP
Value Over Replacement Player. The number of runs contributed beyond what a replacement-level player at the same position would contribute if given the same percentage of team plate appearances. VORP scores do not consider the quality of a player’s defense.
WHIP - BP
Walks plus hits allowed per inning pitched.
WPA - THT
Win Probability Added. A system in which each player is given credit toward helping his team win, based on play-by-play data and the impact each specific play has on the team’s probability of winning.
WS - THT
Win Shares. Invented by Bill James. Win Shares is a very complicated statistic that takes all the contributions a player makes toward his team’s wins and distills them into a single number that represents the number of wins contributed to the team, times three.
