Comparison of Professional Leagues

You can't compair the MLB to Japanese baseball. Their are to many things that are different and the styles of play are totally different.

I must disagree with the above Guest in this case. And the above study does show that it is possible to compare the two. While the styles of play are different, as the Guess points out, such differences should be calculatable from statistics.

The biggest possible flaw in the above study that I can think of is that I believe that it compares players going from the Majors to Pro Yakyu, rather than the other way around. It isn't specified how many of those 66 players got their big break in Japan (like Boomer) before their MLB careers really started, so adjusting from NPB to MLB may be different.

Also, with regard to triples, how many of the 66 players compared were from the time period of smaller stadiums and the Lucky Zone? That would have had the effect of increased home runs in Japan with fewer triples.

Finally, I don't understand the 550 AB baseline. 260,000 at bats divided by 66 players is about 4,000 at bats per player. Is it divided 50/50 between MLB and NPB at bats? I guess I need to buy the book to find out. (And it does sound like a book I would enjoy.)

Nonetheless, those are the only arguements that I can think of to support Guest-san's claims. (I would welcome more arguements against - with evidence.) But as 1908-san pointed out, it was close in predicting a number of Ichiro's stats. Of course it wasn't right on for everything, but it isn't supposed to be. It's an approximation based on statistical analysis and comparisons of different players. A pair of larger variable than style differences between the leagues would be personality of the players and what point in their career they were at (fading/rising) when headed to either JPB or MLB. The tables and/or article don't cover those variables.

If comparing the two leagues is impossible, then why is it that requests for a comparison is one of the most frequently questions I get? I would love to read more statistial comparisons like this one. And since statistical comparisons of the leagues are still in their infancy, their accuracy may not be very high in all aspects, yet. The key word is "yet." As more players cross over from Japan, more data will be collected, and a more accurate set of variables may be derived.

The biggest possible flaw in the above study that I can think of is that I believe that it compares players going from the Majors to Pro Yakyu, rather than the other way around. It isn't specified how many of those 66 players got their big break in Japan (like Boomer) before their MLB careers really started, so adjusting from NPB to MLB may be different.

Good point. Players like Cecil Fielder -- who went from MLB to NPB and then back to MLB -- are included in the study, but I don't know enough about the other players listed to answer your question.

Also, with regard to triples, how many of the 66 players compared were from the time period of smaller stadiums and the Lucky Zone? That would have had the effect of increased home runs in Japan with fewer triples.

Another valid point. A similiar thought occured to me when I first saw the data. I suspect you're right but -- again -- my knowledge of past NPB players is too limited to be certain. I'd re-print the whole table but don't want to step on any copyright toes.

Finally, I don't understand the 550 AB baseline.

550 is the average number of at bats a typical MLB player has in a season. I suspect the author chose that number to make comparisons easier and I just followed his lead. Since we're dealing with ratios, the stats can be adjusted easily to any at-bat number you'd like.

260,000 at bats divided by 66 players is about 4,000 at bats per player. Is it divided 50/50 between MLB and NPB at bats?

No, the split isn't even. The players in question had 90,000 NPB at bats total versus 170,000 MLB at bats. But there are a number of players who had more NPB than MLB at bats across thier careers -- 3, 4 times as many in some cases. The reverse is true, of course. In my opinion, both samples are large enough to make some inferences from.

I guess I need to buy the book to find out. (And it does sound like a book I would enjoy.)

I certainly did. Be forewarned that only 30 pages or so of the book's 200 deal with the Japanese leagues. The best NPB stars are included on the author's Ultimate All-World, All-Star team and discussed some more in that chapter, however. The statisical comparisons alone make the book worthwhile.

I'll bet you'll find this interesting.
http://www.baseballprospectus.com/news/20020129davenport.html

Very much, Peter. Like that article, the aforementioned book also ranks NPB above AAA (see below). The gap between the two is more substantial according to Mr. Davenport's figures, however.

League	AB	H	D	T	HR	BA
MLB	550	143	25	6	19	.260
NPB	550	153	21	1	42	.278
AAA	550	159	26	6	20	.287

Wow! That was an interesting article. That's a site I'm bookmarking now. Hopefully I'll be able to help him with some of his data searching for NPB soon as well.

Some of the terminology was beyond me. I guess I haven't read enough about baseball statistics in English to get all of the technical jargon, yet. But I don't think that'll take long.

Thank you for the link.

More good stuff.

http://www.baseballprospectus.com/news/20020221davenport.html

That sounds like a terrific read. A world-wide effort to creat an international hall of fame could lead to a lot of very interesting research. It will take a thousand baseball fans at a thousand typewriters a thousand years to sort out the vast differences between the leagues and eras. Still, I look forward to someday being able to make meaningful comparisons of Ichiro Suzuki and Oscar Charleston, or Omar Linares and Honus Wagner. Very ambitious!
Did the author attempt to make distinctions between the tendencies of the Pacific and Central Leagues? The disparity in park dimensions may be greater than the disparity between talent levels in the MLB and NPB. I can't see the sense in seeking a baseline that splits the difference. That would make even the best Central League hitters project to lower levels than a half dozen Pacific League sluggers.

It is interesting and I hope it can be done. I also disagree with the guest that it is measurable and comparable. The whole reason sabrmetrics were made was to compare different eras in history as well as different leagues. That is what all these statistics for. A neutral measure of player performance. All are estimated but they give one a good idea of what they would actually do given a large enough sample size. American baseball itself has huge differences from one era to the next not the least the Deadball era or in old Shibe park that a ball was a ground rule double if it was lost in the series of fans seated on the field(you can check it is true). So it is comparable. And I think a joint Hall of fame would be excellent. It would as said would produce terrific amounts of data to help future research.