Inbaseball statistics,slugging percentage (SLG) is a measure of the batting productivity of ahitter. It is calculated astotal bases divided byat-bats, through the following formula, whereAB is the number of at-bats for a given player, and1B,2B,3B, andHR are the number ofsingles,doubles,triples, andhome runs, respectively:
Unlikebatting average, slugging percentage gives more weight toextra-base hits such as doubles and home runs, relative to singles. Batters who excel at getting extra-base hits are sometimes referred to assluggers.[2]Plate appearances resulting inwalks,hit-by-pitches,catcher's interference, andsacrifice bunts orflies are specifically excluded from this calculation, as such an appearance is not counted as anat-bat (these are not factored into batting average either).
The name is amisnomer, as the statistic is not apercentage but an average of how many bases a player achieves per at bat. It is a scale ofmeasure whose computed value is a number from 0 to 4. AMajor League Baseball player's slugging percentage is almost always less than 1 because a majority of at bats result in either 0 or 1 base. The stat awards a double twice the value of a single, a triple three times the value, and a home run four times.[3] The slugging percentage would have to be divided by 4 to actually be a percentage (of bases achieved per at bat out of total bases possible). As a result, it is occasionally calledslugging average, or simplyslugging, instead.[4]
A slugging percentage is usually expressed as adecimal to three decimal places and is generally spoken as if multiplied by 1000. For example, a slugging percentage of .589 would be spoken as "five eighty-nine." The slugging percentage can also be applied as an evaluative tool for pitchers. This is not as common but is referred to as "slugging-percentage against".[5]
As an example: with theNew York Yankees in 1920,Babe Ruth had 458at bats during which he recorded 172 hits: 73 singles, 36 doubles, 9 triples, and 54 home runs.[6] This was(73 × 1) +(36 × 2) +(9 × 3) +(54 × 4) = 388total bases. His total number of bases (388) divided by his total at-bats (458) is .847, which constitutes his slugging percentage for the season.[6]
Ruth's 1920 figure set a record inMajor League Baseball (MLB), which stood until 2001 whenBarry Bonds achieved 411 bases in 476 at-bats for a slugging percentage of .863.[7][8]Josh Gibson, who played inNegro league baseball, had a slugging percentage of .974 in 1937.[8][a]
Until the 2024 incorporation ofNegro league statistics into major league records, the MLB career leader in slugging percentage was Ruth (.6897), followed byTed Williams (.6338) andLou Gehrig (.6324).[10] Ruth was displaced byJosh Gibson, who has a career slugging percentage of .718.[11]
The maximum possible slugging percentage is 4.000.[3] A number of MLB players have had a 4.000 career slugging percentage for a short amount of time byhitting a home run in their first major league at bat. However, no player in MLB history has ever retired with a 4.000 slugging percentage. Four players havetripled in their only MLBplate appearance and therefore share the record—without consideration of a minimum number ofgames played or plate appearances—of a career slugging percentage of 3.000. They areEric Cammack (2000 Mets);Scott Munninghoff (1980 Phillies);Eduardo Rodríguez (1973 Brewers); andChuck Lindstrom (1958 White Sox).[12]
For the 2023 season, the average slugging percentage for all players in MLB was .414. The highest single-season league average was .437 in 2000, and the lowest was .305 in 1908.[13]
Long after it was invented, slugging percentage gained new significance when baseball analysts realized that it combined withon-base percentage (OBP) to form a very good measure of a player's overall offensive production (OBP + SLG was originally referred to as "production" by baseball writer and statisticianBill James). A predecessor metric was developed byBranch Rickey in 1954. Rickey, inLife magazine, suggested that combining OBP with what he called "extra base power" (EBP) would give a better indicator of player performance than typicalTriple Crown stats. EBP was a predecessor to slugging percentage.[14]
Allen Barra andGeorge Ignatin were early adopters in combining the two modern-day statistics, multiplying them together to form what is now known as "SLOB" (Slugging × On-Base).[15]Bill James applied this principle to hisruns created formula several years later (and perhaps independently), essentially multiplying SLOB × at bats to create the formula:
In 1984,Pete Palmer andJohn Thorn developed perhaps the most widespread means of combining slugging and on-base percentage:on-base plus slugging (OPS), which is a simple addition of the two values. Because it is easy to calculate, OPS has been used with increased frequency in recent years as a shorthand form to evaluate contributions as abatter.
In a 2015 article, Bryan Grosnick made the point that "on base" and "slugging" may not be comparable enough to be simply added together. "On base" has a theoretical maximum of 1.000 whereas "slugging" has a theoretical maximum of 4.000. The actual numbers do not show as big a difference, with Grosnick listing .350 as a good "on base" and .430 as a good "slugging." He goes on to say that OPS has the advantages of simplicity and availability and further states, "you'll probably get it 75% right, at least."[16]
