There are many ways to assess baseball players, and there are many schools of thought on what is the best way to do so. Earned Run Average (ERA) is generally the best traditional stat to determine the effectiveness of a pitcher. However, to evaluate hitters, one popular metric to gauge their overall effectiveness is “OPS”.
So, what is OPS in baseball?
OPS, or On-base Plus Slugging, is a statistic that aims to measure the overall effectiveness of a hitter by combining two stats that measure how good he is at reaching base and hitting for power: on-base percentage and slugging percentage.
We’ll go in-depth explaining what OPS is, why it’s useful, and how you calculate it. In the meantime, we’ll dive into the pressing question…
What Is a Batter’s OPS?
On-Base Plus Slugging is a sum of a player’s on-base percentage and slugging percentage. OPS showcases a player’s ability to get on base and hit for power.
On-base Plus Slugging, or OPS, is a combination of a batter’s On-base Percentage (OBP) and Slugging Percentage (SLG). The stat exists to evaluate a batter on both reaching base and hitting for power, the two primary functions that are considered to be the most important for hitters in baseball.
For example, in 2019, the league-wide OBP in Major League Baseball (MLB) was .323 and the SLG was .435. You add these two numbers to get an OPS, and voila, the league OPS in 2019 was .758.
As numbers accumulate, though, these rates will continually change. Because these numbers are ratio based instead of accumulation-based, a stat like OPS is less likely to be thrown wildly out of proportion by a small or larger sample size.
Because a batter’s OPS tends to hold up better than counting numbers over time, it can help assess hitters, even if you’re comparing two players that had a sizeable difference in playing time.
How Do You Calculate OPS?
As we covered earlier, On-Base Plus Slugging or OPS is the sum of a player’s on-base percentage and slugging percentage. Simply put, you can calculate an OPS by just adding the two together. However, if you don’t have those numbers, you can’t calculate a batter’s OPS.
Because the entire OPS equation is comparatively long and difficult to calculate on its own, it is best to calculate OBP and SLG separately and add them. This is because the OBP and SLG formulas have different denominators.
To do so, you can calculate the on-base percentage by adding all hits, walks and hit by pitches, then divide the total by the number of at-bats plus walks, sacrifice flies, and hit by pitches.
Or, you can use plate appearances minus sacrifice bunts as the dominator. As a result, the equation looks like this for OBP:
OBP = (Hits + Walks + Hit by Pitch) / (At bats + Walks + Hit by Pitch + Sacrifice Flies)
The slugging percentage is much simpler to formulate as the equation is simply Total Bases divided by At-bats, or in other words, the number of bases a batter gains from his hits (4 for a homer, 3 for a triple, 2 for a double, 1 for a single).
Once you have those two numbers, you simply add them together and you have your OPS.
For example, let’s say a hitter has 100 at-bats, 30 hits (including 5 doubles, 5 triples, and 5 home runs), ten walks, five hit-by-pitch, and five sacrifice flies.
Using the on-base percentage formula, the hits (30), walks (10), and HBPs (5) numbers add up to 45. The sum of all at-bats (100), walks (10), sacrifice flies (5), and HBP (5) is 120. Dividing 45 by 120, the hitter’s on-base percentage comes out to .375.
On the slugging percentage side, the total bases from singles (15), doubles (10), triples (15) and home runs (20) add up to 60, which dividing by the total number of at-bats (100), comes out to a .600 slugging percentage.
Adding the .375 OBP and .600 SLG, the batter has a .975 OPS.
For the sake of reference, the whole equation lays out like this:
With all that work laid out, it’s probably best to calculate the two numbers separately to keep all the math a little cleaner.
Why Is OPS a Good Stat?
On-base Plus Slugging is one statistic that has mostly hidden in plain sight throughout history and wasn’t viewed to be important until recently.
Among so-called “advanced” metrics, OPS is one of the easiest ones to calculate and use and combines the two numbers generated by the two most important skills for hitters: getting on base and hitting for power.
Because of these two factors, OPS is an easy statistic for fans to find, calculate, and interpret. Additionally, teams can use OPS to measure a player’s ability to get on base and hit for power.
However, OPS is not foolproof by any means.
OPS is a statistic that’s affected by different conditions, such as a ballpark that favors either hitters or pitchers or league-wide conditions that enhance either offense or pitching.
As the Sporting News pointed out in their assessment of OPS, in 2016, David Ortiz led all of MLB with a 1.021 OPS, while in 2000, that figure would have only tied him for the 16th-highest that season.
Likewise, in the 21st century, league-wide OPS figures range from a low of .700 in 2014 to a high of .782 in 2000.
Because OPS is susceptible to ballpark dimensions and league-wide changes, it’s not an end-all, be-all, so another statistic called OPS+ was created to address this.
This stat is much more complex and normalizes a player’s OPS based on league and park factors, using 100 as a baseline. However, we won’t go in-depth into this stat in this article.
What Is a Good OPS in Baseball?
As we mentioned earlier, OPS standards can change over time as leagues and ballparks change. However, there are still general numbers that are considered to be good or bad.
Throughout history, an OPS over .800 has been considered good, with one over .900 being very good and an OPS of 1.000 or higher being elite. On the other side, an OPS below .700 is considered poor and anything below .600 is very poor.
In 2009, baseball statistics pioneer Bill James broke it down further into seven categories (lettered A to G) ranging from “Great” to “very poor.”
He lists a great OPS being over .900, very good beginning at .833, above average at .767, average at .700, below average at .633, poor at .567, and very poor being below .566.
When Did OPS Become a Stat in Baseball?
The components of On-base Plus Slugging (on-base percentage and slugging percentage) have existed for decades. Branch Rickey was at the forefront of the idea of an OPS statistic, having devised the on-base percentage in the 1940s and ’50s.
He also devised a statistic called “Extra Base Power” and even reasoned that the two could be added together to measure a hitter’s overall effectiveness.
As it turns out, Rickey was decades ahead of his time.
OPS didn’t become well-known until the mid-1980s, when amateur statisticians helped establish the concept of OPS. However, it wasn’t until sabermetrics began taking hold in the late 1990s and early 2000s that baseball began to take OPS (and its components) more seriously.
Likewise, on-base percentage was seldom viewed with much importance until the 1990s, while slugging percentage was more widely known earlier because of its association with power hitting.
Despite its usage being well-known and widely accepted today, OPS is not considered an official statistic of Major League Baseball.
That said, today OPS numbers are printed on baseball cards, are readily available on many statistic websites, and in some ballparks are even found in player stats on the scoreboard.
Now the next time you see a batter’s OPS, you have a better idea of whether you can feel good about the guy at the plate, or whether to worry.
Highest Career OPS
The career mark for the highest On-base Plus Slugging belongs to Hall of Famer Babe Ruth, who racked up a 1.164 OPS over his 22-year career. Seven hitters have finished their career with an OPS over 1.000, with Mike Trout straddling that line currently.
Highest Single Season OPS
Barry Bonds holds the single-season record for the highest On-base Plus Slugging, with a staggering 1.422 mark in 2004. He also set an MLB record with a .609 on-base percentage and posted a .812 slugging mark.
What Is Batting Average?
Batting average shows how capable a player is at putting the ball in play and reaching base. Batting average is calculated by taking the total number of hits for a batter and dividing by his total number of at-bats. The stat is useful for determining a player’s effectiveness at the plate but doesn’t factor in walks, sacrifices, etc.