Replacement level is set at a .294 winning percentage in order to maintain continuity with BaseballReference's version of WAR (rWAR).
The PythagenPat method is used when converting runs to wins and also uses .285 as the exponent in the formula.
The Offensive component uses Base Runs to estimate a player's value (in runs) above/below average. Individual player's Base Runs are calculated using the theoretical team method.
LgR/G = League's Runs/Game
RAA = Player's Base Runs above average
G = Player's games played
TmR/G = LgR/G + RAA / G
exponent = (TmR/G + LgR/G)^.285
Offensive WAA = ((TmR/G^exponent / (TmR/G^exponent + LgR/G^exponent))  .5) * G
LgR/G = League's Runs/Game
RAA = Player's Base Runs above average
RAR = Player's Base Runs above replacement
G = Player's games played
oWAA = Offensive Wins Above Average
TmR/G = LgR/G + (RAA  RAR) / G
exponent = (TmR/G + LgR/G)^.285
Offensive WAR = oWAA  ((TmR/G^exponent / (TmR/G^exponent + LgR/G^exponent))  .5) * G
oWAR = Offensive Wins Above Replacement
PA = Player's plate appearances
Offensive WAG = oWAR  (PA / 600) * 3
The Fielding component uses a multiyear average of Defensive Regression Analysis (DRA) to estimate a player's value (in runs saved) above/below average. DRA was created by Michael Humphreys and its method is described in the book Wizardry.
LgR/G = League's Runs/Game
DRA = Player's runs saved above average (from all positions)
G = Player's games played
TmR/G = LgR/G + DRA / G
exponent = (TmR/G + LgR/G)^.285
Fielding WAA = ((TmR/G^exponent / (TmR/G^exponent + LgR/G^exponent))  .5) * G
In order ot maintain continuity, BaseballReference's positional adjustments are used. Positional adjustments are NOT INCLUDED in offensive and fielding WAR.
LgR/G = League's Runs/Game
posR = Player's positional adjustment in runs (from all positions)
G = Player's games played
TmR/G = LgR/G + posR / G
exponent = (TmR/G + LgR/G)^.285
Positional Adjustment = ((TmR/G^exponent / (TmR/G^exponent + LgR/G^exponent))  .5) * G
Pitching WAR is based on runs allowed with an adjustment for a team's fielders.
LgR/G = League's Runs/Game
RAA = Player's runs allowed above average (with positive being better)
G = Player's games played
TmR/G = LgR/G + RAA / G
exponent = (TmR/G + LgR/G)^.285
Pitching WAA = (((TmR/G^exponent / (TmR/G^exponent + LgR/G^exponent))  .5) * G)
LgR/G = League's Runs/Game
RAA = Player's runs allowed above average (with positive being better)
RAR = Player's runs allowed above replacement (with positive being better)
G = Player's games played
pWAA = Pitching Wins Above Average
TmR/G = LgR/G + (RAA  RAR) / G
exponent = (TmR/G + LgR/G)^.285
Pitching WAR = pWAA  ((TmR/G^exponent / (TmR/G^exponent + LgR/G^exponent))  .5) * G
pWAR = Pitching Wins Above Replacement
IP = Player's innings pitched
Pitching WAG = pWAR  (IP / 525) * 2.5

