A Guide to Baseball Sabermetrics


Baseball is truly the sport of the ‘stat junkie’. Many of these stats can be attributed to the system of sabermetrics,  which were first initiated into the sport in the 1980s, and grew exponentially in the 1990s. Sabermetrics really gained traction in the early 2000s, as many of baseball’s front-office decision makers became major advocates of some of these statistics as an alternate way of evaluating players. Sabermetrics derives from the acronym SABR, which stands for the Society for American Baseball Research. The phrase was coined by acclaimed baseball author and researcher Bill James. James and others created new statistics to measure player productivity other than the traditional batting averages and ERA.

In this blog installment, I will outline some of the more widely used stats that have come about as a result of sabermetrics, and how they are calculated. (All are defined from the American Baseball Sabermetrics Glossary)

BABIP: Batting average on balls in Play

The frequency of which a batter reaches a base after putting the ball in the field of play. For pitchers (a measure of the hitters they face), it’s a good measure of luck. So pitchers with high or low BABIPs are good bets to see their performances adjust to the mean.

Def Eff: Defensive Efficiency

The rate at which balls put into play are converted into outs by a team’s defense. Can be calculated with (1 – BABIP).

EqA: Equivalent Average

A stat used to measure hitters independent of ballpark and league effects. It’s a complex formula that 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.

ERA+: Adjusted ERA

Earned run average (for pitchers) adjusted for the ballpark and the league average.

Fielding Runs Above Replacement

The difference between an average player and a replacement player is determined by the number of plays that position is called on to make.

IR: Inherited Runs

The number of runners inherited by a relief pitcher that scored while the reliever was in the game.

ISO: Isolated Power

A measure of a hitter’s raw power – extra bases per at-bat.

LIPS: Late-inning Pressure Situation

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).

Runs created

A term to measure how many runs a player creates. Its basic formula is hits plus walks times total bases, divided by at-bats plus walks.


One of the holy grails of sabermetrics. On-base plus slugging. Measures a batter’s ability to get on base and hit for power. It’s simply the on-base percentage plus the slugging percentage.

WAR or WARP: Wins Above Replacement Player

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

WHIP: Walks & Hits Per Inning Pitched

The average number of walks and hits allowed by the pitcher per inning. (BB + H divided by IP).

All of these statistics are used to evaluate current players, prospective draft picks, and potential free agent targets over the course of the 162 game grind that is an MLB season. By utilizing these statistics, major league teams are able to break through the big data wall and find valuable ‘markers’ that indicate on-field talent. Through the utilization of sabermetrics, baseball teams are becoming smarter in both contract negotiations and lineup selections; providing for a better on-field product to be viewed by the fans.

Drive Home Safely,

Bryan White, MBA



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