Sometimes you hear the phrase adjusted OPS. Adjusted OPS is sometimes also called OPS+, which may or may not help clarify things. So what does adjusted OPS mean? And what is a good adjusted OPS?
What does adjusted OPS mean?
Adjusted OPS attempts to define how a player performs compared to the average player during the same season. It is expressed as a three-digit number, with 100 being an average player. A score of 120 suggests the player is 20% better than average, and a score of 80 suggests that a player is 20% below average.
OPS is the player’s on base percentage plus their slugging percentage. While this is not a perfect statistic, it is a useful one. And it is easy to calculate across the entire league for the year.
What is a good adjusted OPS?
Opinions vary about what a good adjusted OPS would be. It also varies depending on whether you are talking over the course of a season or a career. Average players in baseball are very undervalued. The reason I say that is because the difference between finishing third and going to the World Series usually isn’t the superstars. The difference is usually how many below average players the team has in key roles. The fatal flaw for many teams is not having enough average players.
So from that point of view, any adjusted OPS in the high 90s is a useful player.
An adjusted OPS of around 120 is a superstar. An adjusted OPS of 120 doesn’t guarantee induction into the Hall of Fame, but when you look at borderline Hall of Fame cases, you frequently find they have a career adjusted OPS of around 120.
When you look at the greatest players of all time, during their best seasons, they may have an adjusted OPS of 200 or more. Babe Ruth’s legendary 1927 season wasn’t quite his best. He had an OPS+ of 225 that year, but 239 in 1921 and 1923. Ted Williams matched that in 1941.
Drawbacks of adjusted OPS
Since adjusted OPS is just OPS relative to the league average, it has the same drawbacks that regular OPS does. First of all, it’s just bad math. You are adding two fractions with different denominators. On base percentage has plate appearances as the denominator, while slugging percentage omits walks and hit by pitch.
The other problem is that it counts a walk or a hit by pitch the same as a single. If there’s no one on base, a walk is as good as a hit. And so is a hit by pitch. But a single can allow a runner on base to advance more than one base, and OPS doesn’t factor that in when it happens.
Ozzie Smith is a good example. He did not have a lot of power. When he hit a single, a slow base runner would only move up one base. When Reggie Jackson hit a single, there was a good possibility that a mediocre or even a slow runner would be able to advance two bases. OPS doesn’t factor for any of that.
Also, OPS only factors offense. Ozzie Smith did not have a very impressive adjusted OPS. He worked hard at his hitting and was able to put together some good offensive seasons during his prime, but he wasn’t a great hitter during the early and late parts of his career. He’s in the Hall of Fame because he was an elite fielder.
The problem compounds itself with players who could contribute both offensively and defensively. The case of Dave Parker versus Harold Baines comes to mind. Parker had a very good throwing arm, and reasonable range, and arguably for a couple of years during the late 1970s, he was the best right fielder in the National League. Arguably, Parker was overrated in the field for most of his career, but he played in the field regularly until he was 39.
Harold Baines was a competent right fielder in his prime, but rarely played the field after age 27.
According to OPS+, they are essentially the same player. Parker gets no credit for his contributions in the field. Both Parker and Baines are borderline Hall of Famers. Baines is in the Hall of Fame, and Parker is not. So are Andre Dawson and Jim Rice. With the bat, all four of them are similar players. Dawson was an elite defender until age and injuries reduced his range, but he still had a fearsome throwing arm even late in his career. Rice was a competent fielder but his fielding was closer to Parker than to Dawson. Dawson and Rice are also in the Hall of Fame, and they are controversial because they are borderline.
I think adjusted OPS hides the differences between those four players.
Advantages of adjusted OPS
So adjusted OPS is not a perfect statistic. But I still use it. Overall, I think WAR is a better statistic, but adjusted OPS does a better job of making it obvious which players on a roster are above and below average.
And a big advantage of adjusted OPS is that it measures a player’s season against their peers from the same season. It was harder to hit .400 in 1941 than it was in 1921. It’s even harder today, and that’s the reason no one has hit .400 since 1941. But three players came reasonably close. And you can use adjusted OPS to compare Ted Williams against George Brett, Rod Carew, and Tony Gwynn. Williams hit .406 in 1941. Gwynn hit .394 in 1994. Brett hit .390 in 1980. Carew hit .388 in 1977.
Adjusted OPS does a reasonable job of factoring in the quality of the pitching, the size of the ballparks, the playing surface, the length of the season, and those other non-statistical factors. Ted Williams played in smaller ballparks before integration, so he had an advantage that the other three did not have. His OPS+ of 235 in 1941 beats Brett’s 203 in 1980, Carew’s 178 in 1977, and Gwynn’s 169 in 1994.
So Williams really was otherworldly in 1941. At least with his bat.
So if you want to compare players across eras, adjusted OPS is reasonably good for that. It can’t factor in Willie Mays’s defense, but if the players you are comparing are otherwise similar, you can use it to make fair comparisons.