THE BOOK--Playing The Percentages In Baseball

I know this isn’t the point of the post, but I am somewhat shocked to see that BABIP took such a big jump up in the early 90’s. Is there an agreed upon explanation?

ALL offense stats jumped between 1993-1995.

The likely culprit would be the ball or the bat.

Struggling to remember what exactly he did, but the methodology that MGL used to determine what changed in run environment (and I think found new or young AL pitchers were particularly good or something?) might be interesting to apply to the 1993-1995 run environment jump. If it’s the ball or the bat, it’ll be across the board increase. Of course the reverse statement isn’t true, but it’s more likely be the ball or bat if that were shown I think.

I think there’s an important book or study to be done on the 1993-94 offensive shift.  The most commonly-believed explanations—expansion and PEDs—are at most minor factors.  I don’t think there’s much doubt the ball was juiced, but that may only be part of the answer.  It’s in part a question for sabermetric analysis, but also needs reporting.

The thing is, BABIP is kinda weird. And it doesn’t necessarily track with offensive performance. For example, Barry Bonds had a career BABIP of .285 or so. Mark McGwire was .255. If you want to tell me that ‘roided out sluggers caused BABIPs to climb - at least those two guys were causing it to drop. Sosa was .301, merely average for the period.

I think it would be imprudent to state categorically that a livelier bat or ball would mean higher BABIPs. Certainly it could, but you gotta bring the data - it’s not a slam dunk. I wonder if BABIPs went up sharply at the end of the deadball era.

I would have expected a general downward trend as fielding improves due to better equipment and more talented players. Of course Coors field was introduced to the world about this time and that place played like a pinball machine until the humidor was in place. Plus you have a dilution of talent due to expansion. Those seem minor in the grand scheme of things.

It’s also interesting that the upward trend started around 1969 when the mound was lowered. How that would affect BABIP specifically isn’t clear to me as well. And I would expect to see a dislocation instead of an upward trend over 20 years.

Very curious if you ask me.

#5, Annual BABIP reported here includes the collective data from hundreds of players and thousands of BIP each year and you site Barry Bonds BABIP for 1 year as an example ?

And to answer your question, BABIP did jump sharply at the end of the deadball era, 20 points or so from my brief check on B-ref.

It’s the ball or the bat, or some combo, with the ball likely to be the biggest culprit.

Common sense says that a higher COR for the ball means the speed off the bat is increased, and more balls go for hits (and HR). 

The biggest impact from the bat probably came after 1998 with the harder maple bats becoming more common.  Barry Bonds attributed some of his late career HR success to the use of the maple bat, of course, he had some other help, along with the juiced ball.  The perfect trifecta of juiced bat, juiced balls, juiced body.  Thats a lot of juice.

#5.  Coors field accounted for 3% of the games played.  It could not have explained a 3% rise in BABIP unless BABIP was 600.

The talent pool including increased numbers of latinos and organic growth of population at home actually was increased, even taking into account expansion.  The wars and the lack of complete integration from the 1940’s until 1970 also reduced the talent pool relative to the 90’s.

The mound being lowered likely had a marginal effect.  But baseball went to faster playing surfaces with artificial turf and the introduction of the DH in the AL also improved BABIP (DH have higher BABIP than pitchers, and your worst fielders who were also your best hitters were removed from the defense).

The transition away from the faster and harder artificial turf that started in the late 90’s would have had an adverse effect on BABIP relative to the 70’s and 80’s.

"I think it would be imprudent to state categorically that a livelier bat or ball would mean higher BABIPs.”

The immediate impact would clearly be to raise BABIP.  What’s interesting would be to explore how pitchers and hitters both responded to the new ball over time.  Presumably, hitters increasingly tried to hit the ball in the air (which would lower BABIP).  But pitchers probably started pitching more down in the zone. Perhaps the net effect was a wash. 

One thing that happened quickly was an increase in both Ks and BBs.  But the K/BB ratio stayed the same.  That the net effect helped neither pitchers nor hitters makes me think this was likely a change in approach by batters and/or pitchers, not a change in strike zone. 

The turf issue is interesting.  Does grass reduce BABIP?  I can see reasons it would both increase and decrease it.

I should repeat my study here through 2010, plus, I really really really should repeat it for all the other components too:

http://www.hardballtimes.com/main/article/changes-in-home-run-rates-during-the-retrosheet-years/

“When” though is the question.  I just don’t have the free time I used to have to do stuff like this.

The thing is, BABIP is kinda weird. And it doesn’t necessarily track with offensive performance. For example, Barry Bonds had a career BABIP of .285 or so. Mark McGwire was .255. If you want to tell me that ‘roided out sluggers caused BABIPs to climb - at least those two guys were causing it to drop. Sosa was .301, merely average for the period.

Remember, since BABIP doesn’t count home runs, you’re bound to get lower-than-expected BABIP results for players who hit a large proportion of their fair balls over the fence.  If you add the homers back in for everyone, I’ll bet you get more sensible results…

That’s the difference between “BABIP as a measure of luck” and “BABIP as a measure of how hard a guy hits the ball"…

I just happened to be looking at this issue in another context (discussing with AROM over at BTF how to compare players across historical eras).  The relationship between power and BABIP appears to have changed considerably over time, which I think is really interesting.  In the 1930s, there was a strong positive correlation between a player’s BABIP and his HR/PA—.39.  (Players with at least 2000 PA).  However, for the last decade there was no correlation (-.07).  In today’s game, the BABIP advantage a HR hitter gets from hitting the ball hard is roughly offset by the fact he hits more balls in the air.  That wasn’t true 70 years earlier, presumably because larger outfields and slower OFs made non-HR airballs much more valuable.  Also, I think today’s HR hitters are slower (relative to league average) than the HR hitters of earlier times, which would tend to reduce their BABIP.

Greg,

I well aware that BABIP excludes HR. I’m not looking at BABIP as a measure of luck or as a measure of how hard the ball was hit. It’s a measure of how often the defense allowed balls in play to be hits.

There are three ways this could change:

1. The hitters got better either by hitting the ball harder or hitting it better (ie more line drives).

2. The fielders got worse

3. The environment changed (weather, stadiums, balls, bats)

Now, I’m still not convinced that hitting the ball harder is so obviously going to increase BABIP. I admit it’s a logical presumption, but there are still counteracting factors that make it far from being ‘common sense’. For example: harder hit ground balls are less likely to be infield hits because they are less likely to die in the infield grass and also get to the fielders faster so the fielder has more time to make the play and/or play deeper.

Now in the outfield, harder hit fly balls are home runs so they are removed from the sample.

A person could easily concoct a scenario that doesn’t involved changes to the bat or ball. It could be simply a cultural change where offense was valued more than defense. If you have two players of equal WAR and you choose the one who hits better and fields worse then you will increase BABIP.

I would note that this cultural attitude seems to have changed. Money Ball II seems to be all about defense (pitching and fielding). It will be interesting to see how that affects league BABIPs over the next decade.

Matt/12:  this kind of speculation would be fine, if we didnt’ have evidence. But we do.  BABIP apparently went up in the 1920s, when the ball became livelier.  We also know it went up sharply in 1993-1994, at the same time that HR rates increased.  The only things that could change quickly enough to do this are the ball, bats, and the strikezone.  There is no evidence the strikezone changed dramatically in a way that helped hitters, nor evidence that bat types changed that rapidly.  That leaves the ball. 

Now, maybe the ball has been de-juiced since 1994, and other changes have kept BABIP elevated.  But I think we know that the ball is the main thing that happened in 1993-94. Read Tango’s article if you haven’t.

Guy/13, I don’t think it’s correct to say that we know it was the ball.  That would require COR measurements at game speeds on a sufficient sample of baseballs.

To say it’s the only explanation that has been proposed that seems to be consistent with the facts is probably accurate, but that’s an argument from the other explanations not fitting the facts and not an argument directly based on any evidence about the properties of the ball, AFAIK.

"To say it’s the only explanation that has been proposed that seems to be consistent with the facts is probably accurate.”

That’s good enough for me—this isn’t a criminal court.  YMMV.  I’ve never heard even a vaguely plausible alternative theory that would account for both the HR and BABIP changes.  Tango also mentions some evidence about the balls that is consistent with that conclusion.

Right, it’s either the ball or the bat.  Or we experienced some sort of climate change that “stuck”.  You can look at other leagues (minors, Japan) to see if climate is a possibility. 

Whatever it is, it has to be something that occurred between 1993 and 1995, and it was not some long-range thing, like PED.  It was not change in personnel, because that was controlled for.

***

The HR thing is important.  You hit alot of hard hit balls that go to the gap, and your BABIP is going to go up.  But hit them too hard, and they become HR, and therefore disappear from the numerator and denominator.

So, you have to be very careful in treating BABIP as if it’s some unbiased estimator of something.

Guy/15, I’m not talking about criminal standard of proof here.  I don’t need that.  It’s just that I spent 13 years doing failure analysis, and way too many times did I see people say, prior to analysis and based on the incomplete evidence that they had available, “It’s not W, X, or Y, so it has to be Z.”

Sometimes it really was Z, but very often it either turned out to be something else altogether, or it was Z but in a very different way than people had imagined and thus with different implications, or it really was W, X, or Y because people made incorrect assumptions about the evidence at hand.

So, while I believe that a change in the baseball is the most likely of the possibilities that have been suggested, I don’t see a sound basis for having much confidence in that theory.

Mike:  I don’t think holding out for proof based on the balls is a reasonable standard here.  MLB does not want to allow such testing to occur, even assuming it were still possible.  Blame for the offensive explosion is now fixed on Barry, Sammy, et. al.  Bud and the owners do not want to announce “sorry, it was really our fault.” We have ruled out every other plausible theory, we know a juiced ball would have the effects we see, and we may never have the kind of evidence you want.  Our choices are to believe the ball was juiced, or throw up our hands.  I choose “A.”

Guy, is somebody going to die if throw up my hands and say I don’t know?  What action is awaiting the conclusion here?  Saying I don’t know seems to be something I do a lot more often than other sabermetricians, but I don’t know that I consider that a bad thing.

It’s quite reasonable to say that we don’t believe it was due to steroids or ballparks and that it is plausible that it was due to the ball.  What’s wrong with leaving it at that?

While the ball is the obvious candidate, I wouldn’t rule out the bats.  The bat theory may be plausible because the shift was over two years rather than one.  I’d like to know more about the life cycle of balls being manufactured to being used.  Can a ball be made in late 1993, and then used at some point in 1995, or are they only used in 1994?

With bats, I can see how players will change over a period of 6-18 months, and so, the first jump in 1994, and then further cemented in 1995.

In terms of odds, I guess I’d say:

50% ball
20% bat
10% new strike zone
10% shift in weather pattern across the country/world
9.9% other
0.1% change in personnel or parks (should be 0, but, I guess there’s always a chance)

Well there’s still that upward trend from 1969. Seems unlikely that whatever was causing that just happened to end when the new balls were used.

Matt - Looks to me less like an upward trend and more like a small jump up around 1973 with the introduction of the DH.  A lot more carpeted fields in the 70s and 80s too as another possible explanation.

Tango #20:  bats seem unlikely.  There are many bat manufacturers, but only one ball manufacturer.

Guy, sorry if I came across as snarky in #19.  I’m not sure we differ on the facts here, much if at all.

Mike, if you’re comfortable saying “we don’t know, and probably never will,” I can’t say that’s wrong.  But I’m inclined to go with the high-probability answer, unless/until someone can prove it’s wrong.  I think we both agree that if this were an episode of “House” and we were compelled to make a judgment, we would treat for juiced ball syndrome. 

I’d put the ball probability as more like 80-90% than 50%.  I supposed the strike zone could have shrunk, increasing BBs, and then Ks rose as hitters started swinging more for the fences.  But the problem with both bats and strike zone is they require too large a conspiracy of silence for me to believe.  If umps were told to enforce a dramatically different strike zone, umps and players would talk about it.  And if some players starting using magical bats that boosted HR production by 40%, we’d all hear about that for sure.  The ball is the only factor where information is closely enough held that even 18 years later we still aren’t 100% sure.

The half-way change in 1993 is interesting.  I can think of two possibilities (I’m sure there are others).  #1: the new ball was phased in over the season, mixed with old balls, but in 1994 it was 100% new balls.  #2:  the ball change alone increased HR rates by about 20%.  The additional boost, which took more time, resulted from hitters adapting to the new HR opportunities by modifying their approach (taking more pitches in hopes of seeing a pitch they could drive, modifying swings in some cases).  Or it could be some combination of the two.

I said 1993 to 1995, but I meant 1992 to 1994.  It was cemented in 1994.