OPS: the good-enough shortcut
What if you could get 90% of the fancy stuff by adding two numbers you already know?
OPS is just OBP plus SLG. It's dimensionally nonsensical — the two stats don't even share a denominator — and every statistician winces at it. It's also genuinely useful, which is why it's everywhere from broadcasts to baseball cards.
Why it works anyway
Getting on base and hitting for power are the two things that score runs, and OPS crudely captures both. It correlates with team run scoring almost as well as the proper Level 3 stats. League average floats around .720; .800 is good, .900 is star territory, 1.000 is MVP conversation.
Its real flaw: the simple addition undervalues OBP. A point of on-base is worth almost twice a point of slugging in run terms, but OPS weighs them equally — so it flatters low-OBP sluggers and shortchanges walk machines. When two players' OPS are within ~20 points, trust the one with the higher OBP.
The formula (optional — skippable)
OPS = OBP + SLG
Yes, that's really it.
How this stat lies to you
- It undervalues OBP relative to SLG (~2:1 in real run value, weighted 1:1 here).
- No park or league adjustment — a .850 at Coors ≠ .850 in a pitcher's park (Level 2 fixes this).
- Adding two differently-denominated rates is statistically incoherent — it works by luck, not design.
Check yourself
1. Two hitters, both .850 OPS. A: .400 OBP/.450 SLG. B: .310 OBP/.540 SLG. Whose .850 is probably worth more?
2. Roughly what's a league-average OPS?