When Cubs games air on Marquee Sports Network, opening lineups are displayed with a statistic next to each name: OPS.
We see at a glance that Ian Happ (1.062) ranks with the best, while Javy Baez (.588) and Kris Bryant (.576) do not.
On-base percentage plus slugging percentage is not a perfect stat, but it tells us a lot more than batting average in that OPS accounts for ways of getting on base in addition to hits and hits for extra bases.
Still, fans need context. Those who have an image of a .300 hitter as a star, .280 as pretty good, .250 as average and .220 as dreadful don’t always have as clear an image of what OPS levels mean.
Through Sunday’s games, MLB averages were a .246 BA and .745 OPS. Ten qualifying hitters had BAs of .320 or better. The 10th-highest OPS was 1.010. Going 32 batters deep took you to a .300 BA and .901 OPS, so a .900 OPS ranks roughly as high as a .300 BA.
For an easy rule of thumb, divide OPS by three and you get a BA that ranks about as high. A .750 OPS ranks in the middle, just as a .250 BA does.
Hitters at equivalent BA and OPS levels won’t always be the same players. OPS includes an ability to get on base through walks and hit by pitch, and it includes an ability to move runners around the bases through extra-base hits.
Players who draw walks and hit for power climb the OPS scale. The Cubs’ Anthony Rizzo (.223) and Kyle Schwarber (.221) are in the dreadful BA area but draw enough walks and hit for enough extra bases that their .801 OPSes put them above MLB average.
Happ’s 1.062 OPS ranks fourth in MLB, an advance over the 31st position of his .301 BA.
Those without walks or power slide down the OPS scale. The Orioles’ Hanser Alberto is 11th in MLB with a .318 BA but has a more pedestrian .779 OPS that ranks 85th.
OPS correlates to runs much better than BA does, but there are flaws. It counts singles twice and walks once since singles are included in both OBP and SLG, but walks only in OBP. Singles are more valuable than walks in that they advance more runners, but they’re not twice as valuable.
Derived stats at Fangraphs.com such as weighted runs created plus and weighted on-base average address that problem by assigning weights to offensive events. They also adjust for ballpark and opposition.
Weights are adjusted annually as conditions change, but as a starting point, wOBA multiplies unintentional walks by 0.69, singles by 0.89, doubles by 1.27, triples by 1.62 and home runs by 2.10. Under state-of-the-art metrics, singles are about 1.3 times as valuable as walks, not 2 times as OPS treats them.
OPS can’t tell us everything wOBA and wRC+ do, but it’s an easier calculation. And despite flaws, it tells fans a lot more than batting average does, given the proper context.