"BOP"s explained

[nightwulf]

So I was curious as to how the game determines if a fielder "BOP"s a play. It's a little surprising. Note that throughout this post I'm referring to errors made when fielding a ball (aka "BOP"), and not errors when throwing the ball (overthrown balls that miss the intended baseman).

First off, all fielders on any given team have the same chance to make an error. However, each team has it's own set chance for a BOP to occur on any given play. Here are the numbers per team:

California: 10
Boston: 7
Detroit: 12
Minnesota: 10
Houston: 8
New York: 11
St. Louis: 11
San Francisco: 9
American: 6
National: 4

Here's how it works. Any time a fielder touches the ball after it's been hit but before the ball touches a wall, a subroutine runs to determine whether an error will occur. A random one-byte number (0-255) is generated. If that number is less than your team's number listed above, an error occurs. That is, if you're fielding with St. Louis, you will make a fielding error if the random number is less than 11.

Toss those numbers though a calculator, and you can calculate the percent chance that a fielder will make a fielding error on any given play:

California: 3.9%
Boston: 2.7%
Detroit: 4.7%
Minnesota: 3.9%
Houston: 3.1%
New York: 4.3%
St. Louis: 4.3%
San Francisco: 3.5%
American: 2.3%
National: 1.6%

So, I've not yet looked for the code behind throwing errors (and that would be a hell of a lot harder), but as far as "BOP"s are concerned, every fielder is just as good as any other fielder on his same team. This also brings up a new discovery: the chance for your fielders to "BOP" is different for each team. Of the 8 non-all star teams, Boston is the best-fielding team, with Detroit coming in as the worst. Who would've thought?

Edit: Oh, if you'd like to screw with the numbers yourself, you can find them in the ROM at offset DA92-DA9B. Make that 1DA92-1DA9B if you're editing a 256k ROM. God, there's another thing to add to the editor ...

Nightwulf

[GDavis]

Nightwulf, you are the RBI messiah!

[JoeDirt]

Riley and I have been saying for years that Detroit is the worst fielding team on the game...I have probably even posted as much!

GREAT find, Nightwulf--keep 'em coming!!!!

May I humbly suggest stuff like this gets linked on dee-nee.com?  

[SmokedUBad13]

Nightwulf, I love you with all my heart but I just can't buy this one.  Detroit has always been the most solid fielding team for me with California, Houston, and St. louis being the worst three.  This just doesn't make sense.

Beales
www.rbibaseballcotut.com - The R.B.I. Baseball COTUT

[JoeDirt]

Nightwulf, I love you with all my heart but I just can't buy this one.  Detroit has always been the most solid fielding team for me with California, Houston, and St. louis being the worst three.  This just doesn't make sense.

Beales
www.rbibaseballcotut.com - The R.B.I. Baseball COTUT

Hey Beales...you ever played RBI?  You should give it a try sometime--it's great!

[GDavis]

Nightwulf, I love you with all my heart but I just can't buy this one.  Detroit has always been the most solid fielding team for me with California, Houston, and St. louis being the worst three.  This just doesn't make sense.

Beales
www.rbibaseballcotut.com - The R.B.I. Baseball COTUT

Hey Beales...you ever played RBI?  You should give it a try sometime--it's great!

OH SNAP!!!!

[nightwulf]

Now now, let's play nice. One thing to remember here is that the difference in fielding error probability between teams is very small. So small that it's really not surprising that you may feel the information is incorrect based on your own observations. There's certainly nothing wrong with calling "bullshit" and asking for an explanation.

I wrote up a very detailed explanation of how I came to these figures. Rather than include it in this post (since it's long, and assembler code is nasty) I've attached it as a text file. I'm not sure who here has experience with 6502 assembler (I think Gantry was dabbling in it?) but it's fairly clear if you understand the code.

That said, it's easy enough to set up a demonstration even if you're not familiar with assembler. For example, open up the ROM in a hex editor. Change the value at $DA92 (California's error probability; $0A default) to $00. Change $DA93 (Boston; $07 default) to $FF. Now start the ROM up in an emulator, and setup a "Watch Game" between California and Boston. You'll find that California makes no "BOP"s, while poor Boston is screwed on any eligible play.

These bytes directly control the chance of fielding errors per team. I have nothing against skepticism, but also please understand my position that it's fairly clear to observe the described behavior by either following the game code or changing the appropriate bytes in the ROM and observing gameplay.

Nightwulf

[nightwulf]

For what it's worth, I decided to take my own advice. I modified the ROM so that the two all star teams would make a fielding error on every eligible play (by changing the values at $DA9A and $DA9B to $FF).



Nightwulf

[SmokedUBad13]

Hey Beales...you ever played RBI?  You should give it a try sometime--it's great!

Hey Cordiano... I gave it a try and smoked you bad.  You're right, it was great!

One thing to remember here is that the difference in fielding error probability between teams is very small. So small that it's really not surprising that you may feel the information is incorrect based on your own observations. There's certainly nothing wrong with calling "bullshit" and asking for an explanation.

Yes, this is true.  I did overlook the small difference in probability and went straight to the extreme point of defending that Detroit isn't the worst.  After hearing your explanation and 'proof,' I believe you now.  It's just hard to believe when I have such stong feelings towards Detroit always fielding so well for me.  Then again, there is a certain amount of bad luck in drawing the low number... maybe I'm just lucky enough to draw that random number the least when I'm Detroit.  

Beales
www.rbibaseballcotut.com - The R.B.I. Baseball COTUT

[JoeDirt]

hey now!

[fknmclane]

Nightwulf, you're out of control.  Nicely done.

Smoked, I've always hated fielding with Detroit.  In my experience, they are far and away the worst.  Just fucking terrible.  I can remember two instances where I made FOUR errors in ONE inning with that sack of shit team.  Sorry, I'm getting fired up.  Sometimes I wish Trammell and Sour Lou would spontaneously combust.

[Baines]

I gotta agree with fknmclane about Detroit's fielding.  Three BOP's in the ninth cost me a game with them once.  I still hold bitterness toward DT's fielding to this day.  

I also always hated fielding any ball with the pitcher because I thought they bopped more which I guess isn't true.  I guess maybe it's just due to the fact that it's more memorable when they get bopped on a slow rolling bunt and I end up breaking something.

[fknmclane]

 

I also always hated fielding any ball with the pitcher because I thought they bopped more which I guess isn't true.  I guess maybe it's just due to the fact that it's more memorable when they get bopped on a slow rolling bunt and I end up breaking something.

Savage.

I always thought the pitcher was the worst fielder on every team.  Guess it's just random.

[Gantry]

Wow, color me completely shocked.  Some people have been saying for quite some time that Detroit is the worst fielding team and I have been calling them idiots.  You learn something new about this game everyday...

Some comments and further debate:

1)  This should put to rest the theory that when you sub a batter, they are more prone to BOPs in the field.  

2) On that same note, our superstition that pitchers make more BOPs is completely false.  No that we'll change our strategy

3) Perhaps this is too low-level and involves shit like microcode (if that exists in the NES) and electrical engineering, but do you (nightwulf) have any opinon about hitting the buttons and causing BOPs?  From your explanation there is no provision for it in the assembly, but I am 100% certain that hitting the button too quickly after getting the ball will cause a BOP.  I can't be convinced otherwise, anyone else agree with me?  

I had more ideas, but I'll leave it there for now...

[fknmclane]

3) Perhaps this is too low-level and involves shit like microcode (if that exists in the NES) and electrical engineering, but do you (nightwulf) have any opinon about hitting the buttons and causing BOPs?  From your explanation there is no provision for it in the assembly, but I am 100% certain that hitting the button too quickly after getting the ball will cause a BOP.  I can't be convinced otherwise, anyone else agree with me?  

I had more ideas, but I'll leave it there for now...

Nightwulf and I were discussing this in chat.  As far as he knows, the "jumping the gun" as I call it has no effect.

But I could swear I bop plays with outfielders all the time when I hit the button before I safely have the ball in the glove.

[ultimate7]

Great work again, Nightwulf.  This does confirm the Detroit theory, it really shocks me though that pitchers are not more likely to make BOPS, it always seemed like that had to be true.

[Wilfong]

I always thought NY and StL were the worst fielding teams. You can almost feel when the errors are coming with them. With the exception of Pendleton, has anyone else noticed that he's amazing in the field?
Great work wulf, I'm loving all the insider info I'm getting on this site. I was just busted on throwing out runners at 2nd last night.

[fightonusc]

3) Perhaps this is too low-level and involves shit like microcode (if that exists in the NES) and electrical engineering, but do you (nightwulf) have any opinon about hitting the buttons and causing BOPs?  From your explanation there is no provision for it in the assembly, but I am 100% certain that hitting the button too quickly after getting the ball will cause a BOP.  I can't be convinced otherwise, anyone else agree with me?  

I feel very confident that there is some corrolation here between trying to throw the ball to soon and having a "bop" occur - for me, it's usually on a play to the 2B, when I'm trying to turn the double play.

[ultimate7]

Oh yeah, I forgot about that, If you try to throw too early the chances of making an error go up, I am 95+% certain of this.  I haven't noticed a BOP correlation with the opponent hitting the buttons.

[Gantry]

It's good to know we're not crazy.  Perhaps the opponents button mashing really doesn't do anything, but trying to throw quickly will create more BOPs....

Man, perhaps I'm getting too big of a head in the RBI World.  I am now debunking proven scientific data and making my own claims....