| Statistic | Description | Formula |
| PA | Plate Appearances | AB+BB+HBP+SH+SF |
| TB | Total Bases | 1B + 2*2B + 3*3B + 4*HR |
| XBH | Extra Base Hits | 2B + 3B + HR |
| XBH% | Extra Base Hit Percentage | (2B + 3B + HR) / Hits |
| AVG | Batting Average | H/AB |
| OBP | On Base Percentage | (H+BB+HBP)/(AB+BB+HBP+SF) |
| SLG | Slugging Average | TB/AB |
| OPS | On Base Percentage plus Slugging Average - a quick metric to measure batter performance | OBP+SLG |
| OPS+ | League-adjusted OPS - player OPS relative to the league average OPS, a great way to measure batter performance in a league context: 100 is average. League average OBP (lgOBP) and league average SLG (lgSLG) are computed with pitcher's batting statistics removed. Note: not park adjusted |
100*((OBP/lgOBP)+(SLG/lgSLG)-1) |
| BPF | Batting Park Factor - the home park BPF for a batter. The BPF of each park is calculated once for each season. BPF of 100 is an average park, > 100 is a batter's park and < 100 is a pitcher's park. A BPF of 105 indicates that 5% more runs were scored at that park, by opposing teams, than those teams' average runs per game for the season. BPF is used in the calculation of *lgOBP and *lgSLG, which are then used to convert OPS into a park-adjusted value, OPS+* (see below). Also used to calculate *lgRPG below. |
n/a |
| *OPS+ | League-adjusted, Park-adjusted OPS - similar to OPS+ above, but adjusted for the player's home park BPF, Batting Park Factor. This will adjust players OPS+ depending on whether they played in a good hitter's park (BPF > 100) or a pitcher's park (BPF < 100). Specifically, *lgOBP and *lgSLG are park-adjusted values. Click here for a detailed description of their calculation. Allows more meaningful player comparison by canceling out home park advantages and disadvantages (such as batting at Coors Field for 81 games a season) |
100*((OBP/*lgOBP)+(SLG/*lgSLG)-1) |
| RC | Runs Created - the latest version of Bill James' classic formula, it estimates the number of runs produced by a batter, or team, based on the results of all plate appearances. Originally intended as a Team stat, now used often for individual batters.* Note: may tend to over-value players before 1915 due to the lack of CS and GDP data from that era. |
((H+BB+HBP-CS-GDP)*(TB + (BB+HBP-IBB)*0.24 + SB*0.62 +(SF+SH)*0.5) / (AB+BB+HBP+SH+SF)) |
| xR | Extrapolated Runs - like RC above, estimates the runs created by a batter. This method uses a linear weights formula, which gives each result at the plate a weight and then adds them all together. Being 'linear', individual xR can be added up to find team xR. This is not the case with RC, which must be calculated for a team seperately. A Jim Furtado creation, see his article on xR here. | (.50 * 1B) + (.72 * 2B) + (1.04 * 3B) + (1.44 * HR) + (.34 * (HBP+BB-IBB)) +(.25 * IBB)+ (.18 * SB) + (-.32 * CS) + (-.090 * (AB - H - K)) + (-.098 * K)+ (-.37 * GIDP) + (.37 * SF) + (.04 * SH) |
| RC6 | Runs Created per 600 Plate Appearances - turns the cumulative statistic of Runs Created into a normalized stat per plate appearance, a good way to compare batter performance. | RC*600/(AB+BB+HBP+SH+SF) |
| RC27 | Runs Created per 27 Outs - turns the cumulative statistic of Runs Created into a normalized stat per Out Made by the batter. Since outs are the 'currency' of baseball, meaning teams get 27 outs per game, not a fixed # of PA per game, RC27 is a more relevant stat than RC6 concerning a player's value to his team. If a batter hits into less outs (higher OBP), this results in his teammates, and himself, having more opportunities at the plate, or more PA, in that game. Since the stat is RC per 27 outs, it can also be thought of as how many runs per game a team with the same player in all nine batting order spots would score. Note: not League adjusted or Park adjusted |
RC*27/(AB-H+CS+GIDP+SH+SF) |
| Win Shares | Batting Win Shares - this is the 'short form' version of Bill James' newest metric, Win Shares. Win Shares attempt to measure a player's performance in terms of number of games won. Every Win Share indicates 1/3 of a win contributed to the team. Adding up all players' win shares on a team, including batting, pitching, and fielding, will equal team wins x 3, by definition. The numbers shown in batter queries are Win Shares for batting only. By definition, Win Shares cannot be less than zero. Note: the actual long form of Win Shares, while more accurate, is highly complex, and to attempt to calculate them for all players on the fly here would no doubt require a bank of Cray supercomputers, something I don't have at the moment. |
(RC - (Outs/12))/3 |
| *lgRPG | Park-adjusted League average Runs Per Game - the league average runs scored per game by team, multiplied by the player's Batting Park Factor/100. Also can be thought of the RC27 of a league average player in the batter's home park or parks. This value will then be used to calculate the League-adjusted and Park-adjusted Offensive Winning Percentage, as shown below. | lgRuns*(BPF/100)/lgGames |
| OW% | Offensive Winning Percentage - The theoretical winning percentage of a team with the same player in all nine batting order spots, with league avg defense and pitching, playing against a league average team. (a .740 OW% means 162*0.740 = 120 wins, or a 120-42 record) Perhaps the single best statistic to use in batter performance comparisons across eras. Note: a League adjusted and Park Adjusted stat |
(RC27/*lgRPG)^2 / ((RC27/*lgRPG)^2 + 1) |
| ISO | Isolated Power - a measure of a batter's power, independent of batting avg: equivalent to SLG minus AVG | (TB-H)/AB |
| SecA | Secondary Average - a way to look at a player's extra bases gained, independent of batting average | (TB-H+BB+SB-CS)/AB |
| BBF | Bases on Balls Factor - the number of Plate Appearances per BB | (AB+BB+HBP+SH+SF)/BB |
| SOF | Strikeout Factor - the number of Plate Appearances per Strikeout | (AB+BB+HBP+SH+SF)/SO |
| HRF | Home Run Factor - the number of Plate Appearances per HR | (AB+BB+HBP+SH+SF)/HR |