Definitions

# On-base plus slugging

On-base plus slugging (OPS) is a baseball statistic calculated as the sum of a player's on-base percentage and slugging percentage. The abilities of a player both to get on base and to hit for power, two important hitting skills, are represented, making it an effective way of measuring the player's offensive worth. An OPS of .900 or higher in Major League Baseball puts the player in the upper echelon of offensive ability. Typically, the league leader in OPS will score near, and not necessarily below, the 1.000 mark.

## Formula

The basic formula is

$OPS = OBP + SLG ,$

where OBP is on-base percentage, and SLG is slugging percentage. These percentages are defined

$SLG = frac\left\{TB\right\} \left\{AB\right\}$

and

$OBP = frac\left\{H+BB+HBP\right\} \left\{AB+BB+SF+HBP\right\}$

where:

Since OBP and SLG have different denominators, it is possible to rewrite the expression for OPS using a common denominator. This expression is mathematically identical to the simple sum of OBP and SLG:

$OPS = frac\left\{AB\left(H+BB+HBP\right)+TB\left(AB+BB+SF+HBP\right)\right\}\left\{AB\left(AB+BB+SF+HBP\right)\right\}$

## Interpretation of OPS

Unlike many other statistics, a player's OPS does not have a simple intrinsic meaning, despite its usefulness as a comparative statistic.

One fault of OPS is that it weighs on-base average and slugging percentage equally, although on-base average correlates better with scoring runs. Magnifying this fault is that the numerical parts of OPS are not themselves typically equal (league-average slugging percentages are usually 75-100 points higher than league-average on-base percentages).

## History

On-base plus slugging was first popularized in 1984 by John Thorn and Pete Palmer's book, The Hidden Game of Baseball. The New York Times then began carrying the leaders in this statistic in its weekly "By the Numbers" box, a feature that continued for four years. Baseball journalist Peter Gammons used and evangelized the statistics, and other writers and broadcasters picked it up. The popularity of OPS gradually spread, and by 2004 it began appearing on Topps baseball cards.

The top ten Major League Baseball players in lifetime OPS (with at least 3,000 plate appearances through the end of the 2008 season, active players in bold) are:

1. Babe Ruth, 1.1638
2. Ted Williams, 1.1155
3. Lou Gehrig, 1.0798
4. Barry Bonds, 1.0512
5. Albert Pujols, 1.0489
6. Jimmie Foxx, 1.0376
7. Hank Greenberg, 1.0169
8. Rogers Hornsby, 1.0103
9. Manny Ramírez, 1.0044
10. Todd Helton, 1.0020

Albert Pujols has the highest career OPS for a right-handed batter.

The top ten single-season performances in MLB are (all left-handed hitters):

1. Barry Bonds, 1.4217 (2004)
2. Babe Ruth, 1.3818 (1920)
3. Barry Bonds, 1.3807 (2002)
4. Barry Bonds, 1.3785 (2001)
5. Babe Ruth, 1.3586 (1921)
6. Babe Ruth, 1.3089 (1923)
7. Ted Williams, 1.2875 (1941)
8. Barry Bonds, 1.2778 (2003)
9. Babe Ruth, 1.2582 (1927)
10. Ted Williams, 1.2566 (1957)

The highest single-season mark for a right-handed hitter was 1.2449 by Rogers Hornsby in 1925, (13th on the all-time list). Since 1925, the highest single-season OPS for a right-hander is 1.2224 by Mark McGwire in 1998.

OPS+, Adjusted OPS, is a closely related statistic. OPS+ is OPS adjusted for the park and the league in which the player played, but not for fielding position. An OPS+ of 100 is defined to be the league average. An OPS+ of 150 or more is excellent, while an OPS+ of 50 or less is poor. A problem with basic OPS+ is that it does not make handedness adjustments (right-handers and left-handers). Since there are some parks that hurt a hitter from one side and not on the other, they are not always reflective of pure hitting skill. For example, while Old Yankee Stadium (pre-1976, when drastic park adjustment were made) benefited left-handed hitters, it hurt right-handed hitters. The Yankees however, had an abnormal number of lefties in their lineup in the Joe DiMaggio days, and OPS+ does not make that adjustment.

The basic formula for OPS+ is

$OPS+ = 100\left(frac\left\{OBP\right\} \left\{*lgOBP\right\} + frac\left\{SLG\right\} \left\{*lgSLG\right\} - 1\right)$

where *lgOBP is the park adjusted OBP of the league and *lgSLG is the park adjusted SLG of the league.

A common misconception is that OPS+ closely matches the ratio of a player's OPS to that of the league. In fact, due to the additive nature of the two components in OPS+, a player with an OBP and SLG both 50% better than league average in those metrics will have an OPS+ of 200 (twice the league average OPS+) while still having an OPS that is only 50% better than the average OPS of the league.

Through September 28, 2008, the career leaders in OPS+ (minimum 3,000 plate appearances, active players in bold) were

1. Babe Ruth, 207
2. Ted Williams, 191
3. Barry Bonds, 182
4. Lou Gehrig, 179
5. Rogers Hornsby, 175
6. Mickey Mantle, 172
7. Dan Brouthers, 170
8. Joe Jackson, 170
9. Albert Pujols, 170
10. Ty Cobb, 167
11. Jimmie Foxx, 163

The highest single-season performances were:

1. Barry Bonds, 268 (2002)
2. Barry Bonds, 263 (2004)
3. Barry Bonds, 259 (2001)
4. Fred Dunlap, 258 (1884)
5. Babe Ruth, 256 (1920)
6. Babe Ruth, 239 (1921)
7. Babe Ruth, 239 (1923)
8. Ted Williams, 235 (1941)
9. Ted Williams, 233 (1957)
10. Ross Barnes, 231 (1876)
11. Barry Bonds, 231 (2003)

Source: www.baseball-reference.com