Sabermetrics Formulas

Sabermetrics uses statistical analysis digging deep into analyzing baseball records. It aids in making determinations about players performances. The practice began in 1977 when Bill James began self-publishing works about a new discipline he called sabermetrics.

Sabermetrics was more recently popularized by the movie Moneyball which depicted how Billy Beane, the Oakland A’s General Manager, used sabermetrics in 2002.

I personally go by feel of the game to make judgement about individual players, but here’s a quick look at some of the sabermetrics formulas:

Adjusted ERA (ERA+): Earned run average adjusted for the ballpark and the league average.

Batting Average on Balls in Play (BABIP): The frequency of which a batter reaches a base after putting the ball in play. For pitchers it’s usually a measure of luck. So, pitchers with high or low BABIP’s are a good bet to see their performances adjust to the mean.

Base Runs (BsR): Estimates the number of runs a team “should” have scored given their component offensive statistics.

Component ERA (CERA): An estimate of a pitcher’s ERA based upon the individual components of his statistical line, another statistic that tries to take luck out of the equation.

Defensive Efficiency (Def Eff): The rate at which balls put into play are converted into outs by a team’s defense. This can be approximated with (1 – BABIP).

Defense-Independent ERA (DERA): This is a measurement of what a pitcher’s earned run average would have been, if not for the effects of defense and luck. It uses batters faced, home runs allowed, walks allowed, intentional walks allowed, strikeouts and hit batsmen in a complex mathematical formula.

Defense Independent Component ERA (DICE): Formula that measures pitching performance using home runs allowed, walks, hit by pitch, strikeouts and innings pitched.

Defense Independent Pitching Statistics (DIPS): A series of statistics that measure a pitcher’s effectiveness based only on plays that do not involve fielders: home runs allowed, strikeouts, hit batters, walks, and, more recently, fly ball percentage, ground ball percentage and line drive percentage.

Equivalent Average (EqA): A stat used to measure hitters independent of ballpark and league effects. EqA takes into account hits, total bases, walks, hit by pitch, stolen bases, sacrifice hits, sacrifice flies, at-bats and caught stealing. It’s then normalized for league difficulty.

Extrapolated Runs (XR): Similar to runs created, except it assigns a run value to each event, rather than a multiplicative formula.

Fielding Runs Above Replacement: The difference between an average player and a replacement player, determined by the number of plays that position is called on to make.

Inherited Runs (IR): The number of runners inherited by a relief pitcher that scored while the reliever was in the game.

Isolated Power (ISO): A measure of a hitter’s raw power – extra bases per at-bat.

Late-inning Pressure Situation (LIPS): Any at-bat in the seventh inning or later, with the batter’s team trailing by three runs or less (or four runs if the bases were loaded).

On-base plus slugging (OPS): Measures a batter’s ability to get on base and hit for power. It’s simply the on-base percentage plus the slugging percentage.

Peripheral ERA (PERA): A pitching statistic that computes the expected ERA, taking into account park-adjusted hits, walks, strikeouts and home runs allowed.

Player Empirical Comparison and Optimization Test Algorithm (PECOTA): Named for baseball player Bill Pecota. It’s a very complex formula that forecasts a player’s performance in all of the major categories used in common fantasy baseball games and in forecasting production in advanced sabermetric categories.

Pythagorean expectation: A formula that resembles the mathematical Pythagorean theorem and is used to estimate how many games a baseball team should have won, based on how many runs a team scored and allowed. Comparing the two percentages can determine how lucky a team was.

Quality Start (QS): A game in which a pitcher completes six innings, allowing no more than three runs.

Range Factor (RF): Used to determine how much field a player can cover. It’s nine times putouts plus assists divided by innings played.

Runs created: Measures how many runs a player creates. Runs created formula is hits plus walks multiplied by total bases, divided by at-bats plus walks.

Total Player Rating (TPR): It measures the value of players that allows players to be compared for different positions, teams and eras.

Value Over Replacement Player (VORP): For hitters, it’s the number of runs contributed beyond what a replacement-level player at the same position would contribute.

Win Shares: Using a set of complex mathematics, it takes into consideration statistics for players in the context of their team, and assigns them a number that’s one-third of a teams wins.

Wins Above Replacement Player (WARP): A statistic that combines win shares and VORP. It represents the number of wins this player contributed, above what a replacement level hitter, fielder and/or pitcher would have done.

Walks and Hits Per Inning Pitched (WHIP): The average number of walks and hits allowed by the pitcher per inning.

Study these sabermetrics formulas and maybe you can become the next Billy Beane.