On-base plus slugging (OPS) is a baseball statistic that attempts to measure a player's offensive performance. Specifically, it combines on-base percentage (OBP) and slugging percentage (SLG).
Many people look at OPS as a valuable tool for assessing the offensive skill of a player. On the other hand, critics say that it undervalues on-base percentage and over-values extra-base hits, thus misrepresenting a hitter's value to his team.
Components of On-base plus Slugging (OPS)
The first component of OPS is on-base percentage (OBP), which measures a player's ability to get safely on base.
A player's on-base percentage is the sum of hits (H); walks, or bases on balls (BB); and times hit by a pitch (HBP), divided by the sum of official at-bats (AB), walks, sacrifice flies (SF) and times hit by a pitch. The formula looks like this:
The other component of OPS is slugging percentage (SLG), which measures a player's ability to get hits, especially extra-base hits (ie. doubles, triples, and home runs).
Slugging percentage is calculated by dividing the total bases (TB) a player achieves on hits by the number of official at-bats (AB). A single (1B) is one base, a double (2B) is two bases, a triple (3B) is three bases, and a home run (HR) is four bases. The formula for slugging percentage is simple:
The slugging percentage formula can also be written this way:
On-base plus slugging is simply the player's on-base percentage plus his slugging percentage. The formula can be written simply as:
A longer version of the OPS formula, with all of the components included, can be written as:
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Among active players, the career OPS leader is Mike Trout of the Los Angeles Angels, who has an OPS of .9999 as of June 2020.
OPS vs. Batting Average
Many people consider OPS to be useful for measuring a batter's skills. Getting on base without an out being recorded correlates well with helping a team score runs. This is true no matter how the player gets on base, which is why on-base percentage is often considered a better measure of a batter's contributions to the team than batting average, which is calculated by dividing the number of hits by the number of at-bats. Batting average, for example, doesn't give the batter credit for drawing a walk.
OPS also rewards a batter's ability to get hits, especially extra-base hits, by including slugging percentage as a component. A double is usually more valuable to a team than a single, and this is reflected in the OPS formula. Home runs are the most valuable type of hit, so the OPS formula gives them the most weight.
OPS in Major League Baseball
In Major League Baseball, the average OPS is about .750, although this fluctuates from season to season, and can be especially dependent on the strength of MLB pitchers in a particular year.
An OPS of 1.000 is considered outstanding for a major league player. In most seasons, only a few players who have batted more than 500 times achieve an OPS of 1.000. As of 2020, just seven players in MLB history have retired with a career OPS of 1.000 or better. The career OPS record is held by slugger Babe Ruth, who had a career OPS of 1.1636 when he retired in 1935.
MLB players who retired with a career OPS of 1.000 or better:
- Babe Ruth (1.1636)
- Ted Williams (1.1155)
- Lou Gehrig (1.0798)
- Barry Bonds (1.0512)
- Jimmie Foxx (1.0376)
- Hank Greenberg (1.0169)
- Rogers Hornsby (1.0103)
OPS Outside of the Major Leagues
At lower levels of baseball, such as in high school or youth leagues, highly skilled players are often able to achieve much higher averages in various batting statistics, including OPS. This is because there is a much wider range in the skill levels of batters and pitchers at this level than in the major leagues. For example, a great high school hitter might face lesser-skilled pitchers on a regular basis, whereas a major league hitter will usually face very talented pitchers.
Therefore, at lower levels of baseball, players are more accurately assessed by comparing their statistics to those of their peers, rather than to those of major league players.
Criticisms of OPS
Although many people consider OPS to be a useful tool, critics have pointed out several potential shortcomings of this statistic. These relate to how valuable a hitter's various outcomes are to the team and how well certain statistics correlate to a team's success. For example, on-base percentage (OBP) is more directly linked to team success than slugging percentage (SLG), but the OPS formula gives the two statistics equal weight.
Another criticism of OPS is specifically pertains to the formula for slugging percentage (SLG). According to the SLG formula, a double is worth twice as much as a single, a triple is worth three times as much, and so on. In terms of value to the team, however, the difference between the types of hits has been found to be much less.
Depending on the method used to calculate the value of each type of hit to the team, a double has been found to be worth only about 40% to 60% more than a single, with a triple being worth about 70% to 130% more and a home run worth about 120% to 200% more. Thus, slugging percentage, and therefore OPS, is considered by some critics to overvalue extra-base hits.