Glossary - Seamheads Negro Leagues Database

Glossary

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Baseball Gauge Wins Above Replacement (gWAR)

Replacement Level

Replacement level is set at a .294 winning percentage in order to maintain continuity with Baseball-Reference's version of WAR (rWAR).

Pythagorean Winning Percentage

The PythagenPat method is used when converting runs to wins and also uses .285 as the exponent in the formula.


Offense

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.

WAA (Wins Above Average) Formula

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

WAR (Wins Above Replacement) Formula

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

WAG (Wins Above Greatness) Formula

oWAR = Offensive Wins Above Replacement
PA = Player's plate appearances

Offensive WAG = oWAR - (PA / 600) * 3



Fielding

The Fielding component uses a multi-year 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.

Formula

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



Positional Adjustment

In order ot maintain continuity, Baseball-Reference's positional adjustments are used. Positional adjustments are NOT INCLUDED in offensive and fielding WAR.

Formula

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

Pitching WAR is based on runs allowed with an adjustment for a team's fielders.

WAA (Wins Above Average) Formula

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)

WAR (Wins Above Replacement) Formula

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

WAG (Wins Above Greatness) Formula

pWAR = Pitching Wins Above Replacement
IP = Player's innings pitched

Pitching WAG = pWAR - (IP / 525) * 2.5


If you have any questions regarding Negro Leagues statistical or biographical data, please contact gary@seamheads.com. For any other questions/comments/suggestions, please contact the web developer at BaseballGauge@gmail.com.

Statistical and biographical data for the The Negro Leagues Database, except 1923 and 1933, were compiled by Gary Ashwill. Copyright 2011-2013 Gary Ashwill. All rights reserved. Playing statistics for 1923 were compiled by Patrick Rock. Copyright 2011-2013 Patrick Rock. All rights reserved. Playing statistics for 1933 were compiled by Scott Simkus. Copyright 2013 Scott Simkus. All rights reserved.


Defensive Regression Analysis data used here was obtained with permission from Michael Humphreys, author of Wizardry

Win Shares are calculated using the formula in the book Win Shares by Bill James