Why are Baseball stats-masters obsessed with OPS?

Question

Onbase plus slugging seems like a bit of a nonsense statistic. Each of them is quite important on their own, but as a basis of comparison, it seems silly. For a lead-off hitter, OBP is more important, for someone in the middle of a lineup, SLG is more important. Yet this stat adds them at a 1:1 ratio, uses it as a baseline for comparison, and all the analyists LOVE the stat.

Answer 1

Pfft; real analysts are well beyond OPS, which is SOOO 1980s.

It's a good quick-n-dirty stat for making comparisons between players. OPS by itself doesn't measure anything quantitative because the math involved is nonsense; it adds two ratios with dissimilar denomenators, and that is a huge cheat in real math. But for comparative purposes, OPS rocks -- it is easy to calculate and uses readily-available data. It is not complicated, and that's pretty sweet. There are better calculated metrics, but none quicker.

EVERY batter in the lineup has two tasks: get on base, and advance standing baserunners. This is how runs are scored, and the scoreboard doesn't care how the runs are scored or who scores them. OBP captures the "get on base" aspect pretty well, and SLG the "advance runners" side. So OPS gives a (somewhat imperfect) roll-up of a hitter's performance at both tasks and does it fast. Given two players with approximately equal plate appearances, you generally want the one with the higher OPS if other aspects (position, defensive skill there, durability, etc.) are equal. Find someone with an OPS over 1.000 (and really, the decimal point is meaningless for the math reasons described above, but it hangs on with traditional tenacity) and you've got a rare bird.

As you note, the 1:1 ratio is one of the failings of OPS, and there are ways to compensate that, but such does complicate the otherwise simple math that makes OPS so beautiful. A point of OBP is harder to come by than a point of SLG, so between two players with equivalent OPS you'd probably prefer the one with the higher OBP and sacrifice a little SLG; and there is nothing wrong with this. But for the usual purposes that OPS serves -- comparative, and quick to calculate -- it works well. There are finer scalpels, sure, but this one stat typically makes a good enough cut.

Answer 2

I'm a bit of a stats geek myself, and I do see your point. I value OPS, but it can't be seen as a standalone statistic.

Like you said, slugging percentage isn't exactly a requirement for a leadoff hitter, but would be more important for your middle-of-the-lineup guys. Personally, I value OBP more than slugging percentage, no matter where a guy bats in the order.

It definitely shouldn't be seen in that 1:1 ration, and the two pieces of the equation don't measure the same thing. It's a handy quick stat to reference, but there are better ones out there. I'd rather look at things like Runs Created or VORP to measure value than to rely on OPS.

Answer 3

The true statheads don't care about OPS - they pay attention to made-up, obscure statistics that take about 10 pages to fully explain. Caring a lot about OPS is a shorthand way of saying "someone once told me that batting average isn't a good measure of hitting ability, but I don't really understand why."