Why is league OPS+ below 100?

[reviewboy1]

I apologize if this has been discussed already, but I can't seem to find the answer by searching.

I noticed that on baseball-reference.com the league average OPS+ for all teams, combined, is often well below 100. For example, for 2012 NL the league overall OPS+ is 94.

I would have expected that the league average would be exactly 100, but maybe I fundamentally misunderstand this stat.

Could someone please enlighten me as to how this stat, ostensibly normalized to 100, would be well below 100 for the entire league?

Thanks.

[Bothrops Atrox]

I apologize if this has been discussed already, but I can't seem to find the answer by searching.

I noticed that on baseball-reference.com the league average OPS+ for all teams, combined, is often well below 100. For example, for 2012 NL the league overall OPS+ is 94.

I would have expected that the league average would be exactly 100, but maybe I fundamentally misunderstand this stat.

Could someone please enlighten me as to how this stat, ostensibly normalized to 100, would be well below 100 for the entire league?

Thanks.

Something to do with pitchers' batting? Is the AL always normalized at 100?

[reviewboy1]

Matthew -

That's an interesting observation.

I'm looking at AL league OPS+ a season at a time, working backward from 2012.

2004-2012 all have an AL OPS+ of 100.

2003 has an AL OPS+ of 99.

For 2000-2002 it's 100.

For 1999 it's 99.

For 1998 it's 100.

[reviewboy1]

I think that I found the answer, here:

http://www.hardballtimes.com/main/blog_article/how-is-this-possible1/

Apparently the 'issue' (if you want to call it that) is that pitchers are excluded from OPS calculation but included in OPS+ calculation.

[dominik]

yes, pitchers are excluded.

[Ben Grimm]

Just asking since I'm sure I'm not the only one clueless...

If Player A has a 120 OPS+ in the AL, would it be the same relative to the NL? See, what I'm asking is a player in the NL given the OPS+ benefit because the benchmark is 94 as opposed to 100?

[Jackaroo Dave]

Just asking since I'm sure I'm not the only one clueless...

If Player A has a 120 OPS+ in the AL, would it be the same relative to the NL? See, what I'm asking is a player in the NL given the OPS+ benefit because the benchmark is 94 as opposed to 100?

Ben, here is the method for calculating ops+ from baseball-reference.com/about > batting glossary. It is a lot more complicated than I thought, but it seems clear that individual Ops+ is league- not MLB oriented.

Note that RC becomes RC' when the park factor is introduced. I believe park factors are calculated over 3 years running, so it's possible for league Ops+ not to equal 100%, using only that league's data, if the park factors vary in concert. It would all depend at what stage the league ops+ gets published.

Compute the runs created for the league with pitchers removed (basic form) RC = (H + BB + HBP)*(TB)/(AB + BB + HBP + SF)
Adjust this by the park factor RC' = RC*BPF
Assume that if hits increase in a park, that BB, HBP, TB increase at the some proportion.
Assume that Outs = AB - H (more or less) do not change at all as outs are finite.
Compute the number of H, BB, HBP, TB needed to produce RC', involves the quadratic formula. The idea for this came from the Willie Davis player comment in the Bill James New Historical Baseball Abstract. I think some others, including Clay Davenport have done some similar things.
Using these adjusted values compute what the league average player would have hit lgOBP*, lgSLG* in a park.
Take OPS+ = 100 * (OBP/lgOBP* + SLG/lgSLG* - 1)
Note, in my database, I don't store lgSLG, but store lgTB and similarly for lgOBP and lg(Times on Base), this makes calculation of career OPS+ much easier.

[Ben Grimm]

Ben, here is the method for calculating ops+ from baseball-reference.com/about > batting glossary. It is a lot more complicated than I thought, but it seems clear that individual Ops+ is league- not MLB oriented.

Note that RC becomes RC' when the park factor is introduced. I believe park factors are calculated over 3 years running, so it's possible for league Ops+ not to equal 100%, using only that league's data, if the park factors vary in concert. It would all depend at what stage the league ops+ gets published.

Thanks Dave! I guess I'll need to read into it more to get a better feel for it.

[Jackaroo Dave]

Thanks Dave! I guess I'll need to read into it more to get a better feel for it.

The BBREF /about page has a bunch of stuff, though not as much as i'd like.

[GiambiJuice]

In the National League in 1930, Pinky Whitney hit .342/.383/.465, 207 hits, 41 doubles, 117 RBI, only 41 strikeouts in 660 PA's... His OPS+ was 98. Just wow.