- Link to baseball-reference.com: The intent of these pages is to present my runs and wins over replacement ratings, not to reproduce another online baseball encyclopedia. I think that function has been covered more completely than I could hope to do, so I have provided a link in case people want to compare these ratings to the full stat lines.
- PA - Plate Appearances, actually at bats plus walks plus hit by pitches, so this will not match with official PA totals. In addition, I only have seasons from 1955, so totals will not include the entire career for many players.
- Bat runs - This is park adjusted linear weights batting runs, using customized weights at the team level to ensure that total runs credited to players will equal the actual runs scored for that team.
- BSR - Baserunning runs. Includes stolen bases, advancement on hits, outs, wild pitches, passed balls, and outs made on bases. This is estimated from a regression formula for seasons without play by play data.
- GIDP - Runs from hitting into double plays, above or below average considering a player's GIDP opportunities. A GIDP opportunity is a groundball fielded by an infielder with less than two out and a runner on first base.
- ROE - Reached on error. Runs from hitting into more or fewer errors than average.
- TZ- TotalZone, a measure of defensive range based on analysis of retrosheet play by play data. For seaons before 1953, and the 1953 American League, This measure is based on a much cruder formula called JAARF (Just another adjusted range factor.) which estimates defensive ratings from assists, putouts and errors, as well as team hits allowed by lefthanded and righthanded pitchers.
- ifDP - For infielders, double play runs compared to average based on DP opportunities
- ofArm - Outfielder arm ratings, from how many baserunners they allow to advance, hold, or throw out compared to average based on opportunities
- Catch - Catcher ratings based on stolen bases allowed, caught stealing, errors, wild pitches, passed balls, and pickoffs. Catchers are compared to the yearly league average, with the averages splits catching lefthanded and righthanded pitchers
- Pos - Position adjustment - based on how players perform at multiple positions. I have made separate position calculations by decade.
- Rep - The difference between a league average player and replacement level. This is normally 20 runs per season (650 PA), but varies slightly depending on the strength of the league. Currently, the American league is stronger than the National league, but 50 years ago the opposite was true
- RAR- Runs above replacement - a total of the columns listed above
- WAR- Wins above replacement - Runs above replacement divided by a runs to wins converter. This is normally close to 10 runs per win but is less in lower run scoring environments
- IP, Runs - Actual Innings pitched and runs allowed totals
- Rep - Estimated runs that a replacement level pitcher would allow, given this pitcher's opponents, ballpark, league, and defensive support
- Def - Estimated runs saved by this pitcher's defense, using TotalZone range, DPs, OF arms, and catchers, prorated by the number of balls in play allowed by the pitcher
- LI - Leverage Index, licensed from Inside the Book, which measures the win impact of the game situation faced by each pitcher
- WAR- Wins above replacement - Runs above replacement, adjusted for leverage, divided by a runs to wins converter. This is normally close to 10 runs per win but is less in lower run scoring environments. Pitchers are credited with extra leverage halfway between their actual leverage and 1.0. This is due to the effect of chaining, a relief ace who normally has a leverage of 2.0 and is injured. He will be replaced by a setup man, who is normally an above average pitcher himself, and all pitchers will move up into higher impact situations. The net effect is less than if we assume that the relief ace is directly replaced by a replacement level pitcher.
- R+ - Runs allowed above or below league average. Unadjusted for any context.
- BB+ - Run value of walks allowed above or below league average given batters facing pitcher. Unadjusted for any context.
- HBP+ - Run value of hit batsmen allowed above or below league average given batters facing pitcher. Unadjusted for any context.
- SO+ - Run value of strikeouts above or below league average given atbats against pitcher. Unadjusted for any context.
- HR+ - Run value of homeruns allowed above or below league average given number of fair contacted balls allowed. Unadjusted for any context.
- Hit+ - Run value of hits allowed above or below league on balls in play. Unadjusted for any context.
- X - Runs saved or allowed beyond measurable impact of hits, homers, walks, strikeouts, and HBP. This is a catch-all category that includes holding and picking off runners, defensive support including the DP, errors in the field, timing of events (pitching better or worse with runners on base), or any other explanation you can think of.