Statistics questions -RBI's got vs chances?

Statistics questions -RBI's got vs chances?

Post by Laurence Ch » Sat, 16 Jul 1994 05:24:07


Being new to baseball (not an American) I am often impressed by all the
stats the game produces (BP, OBP, SLG, RBI, HR etc.) But it seems to me,
perhaps somewhat naively, that RBI's isn't really a true reflection of
the ability to hit in runs. I know I often see flash on the screen the BP
of someone with runners on base. But is there a way to measure RBI's
gained versus chances - i.e. who is the better batter, someone who has 50
RBI's but batted a run in 80% of the time he had the chance to do so, of
someone with 80 RBI's but only had a 50% average in the same respect. The
second guy had more chances but he didn't capitalize as well as the first
guy.

If this sounds silly then advance apologies - I clearly don't understand
this game at all.

Laurence Chiu

 
 
 

Statistics questions -RBI's got vs chances?

Post by 15.. » Sat, 16 Jul 1994 00:43:04

Quote:

> Being new to baseball (not an American) I am often impressed by all the
> stats the game produces (BP, OBP, SLG, RBI, HR etc.) But it seems to me,
> perhaps somewhat naively, that RBI's isn't really a true reflection of
> the ability to hit in runs. I know I often see flash on the screen the BP
> of someone with runners on base. But is there a way to measure RBI's
> gained versus chances - i.e. who is the better batter, someone who has 50
> RBI's but batted a run in 80% of the time he had the chance to do so, of
> someone with 80 RBI's but only had a 50% average in the same respect. The
> second guy had more chances but he didn't capitalize as well as the first
> guy.

> If this sounds silly then advance apologies - I clearly don't understand
> this game at all.

> Laurence Chiu


You may understand it better than you think.  Lots of statistics can
be misleading or unfair.  One reason high RBI producers have lots of
RBIs is that they are put in a position to knock in runs more often.
(The rich get richer, the poor get poorer).

Another stat that needs replacing is measuring relievers by their ERA.
While ERA may be a good measure for starters, it is poor for relievers
because it doesn't take into account how effective the reliever is in
keeping the runners ("belonging" to another pitcher) who are on when
he comes in from scoring.

Anyone have a better way to rate relievers?

--
-------------------------------------------------------------------
Frank Knight               E-mail:


-------------------------------------------------------------------

 
 
 

Statistics questions -RBI's got vs chances?

Post by unkno » Sat, 16 Jul 1994 06:33:24

Quote:

>Being new to baseball (not an American) I am often impressed by all the
>stats the game produces (BP, OBP, SLG, RBI, HR etc.) But it seems to me,
>perhaps somewhat naively, that RBI's isn't really a true reflection of
>the ability to hit in runs. I know I often see flash on the screen the BP
>of someone with runners on base. But is there a way to measure RBI's
>gained versus chances - i.e. who is the better batter, someone who has 50
>RBI's but batted a run in 80% of the time he had the chance to do so, of
>someone with 80 RBI's but only had a 50% average in the same respect. The
>second guy had more chances but he didn't capitalize as well as the first
>guy.

>If this sounds silly then advance apologies - I clearly don't understand
>this game at all.

>Laurence Chiu


This is not silly at all.  In fact, I wish more people didn't
understand the game as well as you.  RBI's vs chances is sort of
difficult for a number of reasons:  1)  what constitutes a chance?
a runner on first?  A runner on second?  Third?  Two of the three?
2)  Do home runs count as rbi chances?  3)  Does rbi/chance really tell
you about the better hitter?  For example, is an rbi at the cost of an out
better than a no rbi but not an out (ie a walk)?

These are the types of questions that I would ask.  BTW, the rbi% numbers
are available from STATS, Inc.  For the most part, they represent SLG.

paul

 
 
 

Statistics questions -RBI's got vs chances?

Post by unkno » Sat, 16 Jul 1994 08:24:36

Quote:

>Another stat that needs replacing is measuring relievers by their ERA.
>While ERA may be a good measure for starters, it is poor for relievers
>because it doesn't take into account how effective the reliever is in
>keeping the runners ("belonging" to another pitcher) who are on when
>he comes in from scoring.

>Anyone have a better way to rate relievers?

I have seen a proposal here of "Expected runs saved" in which you
subtract number of runs allowed from runs expected for each situation
(my apologies to whomever did that, it's been a while), but it
seems pretty complicated in that you need lots of situational data.

OTOH, if the relievers don't give up hits and walks, they will probably
be better at keeping runners from scoring.  Thus, I think slg and out%
are are reasonable measures.  For one thing, since relievers pitch
more often with runners on base, it's not as likely to succomb to
'clutch pitching' (ie pitching better from the stretch than usual)
problems.  Of course, so's and ground balls are more desirable from
relievers, but hopefully the effect is small.

paul

 
 
 

Statistics questions -RBI's got vs chances?

Post by Doug Bowm » Sat, 16 Jul 1994 06:51:29


Quote:


>>Being new to baseball (not an American) I am often impressed by all the
>>stats the game produces (BP, OBP, SLG, RBI, HR etc.) But it seems to me,
>>perhaps somewhat naively, that RBI's isn't really a true reflection of
>>the ability to hit in runs. I know I often see flash on the screen the BP
>>of someone with runners on base. But is there a way to measure RBI's
>>gained versus chances - i.e. who is the better batter, someone who has 50
>>RBI's but batted a run in 80% of the time he had the chance to do so, of
>>someone with 80 RBI's but only had a 50% average in the same respect. The
>>second guy had more chances but he didn't capitalize as well as the first
>>guy.

>>If this sounds silly then advance apologies - I clearly don't understand
>>this game at all.

>>Laurence Chiu

>This is not silly at all.  In fact, I wish more people didn't
>understand the game as well as you.  RBI's vs chances is sort of
>difficult for a number of reasons:  1)  what constitutes a chance?
>a runner on first?  A runner on second?  Third?  Two of the three?
>2)  Do home runs count as rbi chances?  3)  Does rbi/chance really tell
>you about the better hitter?  For example, is an rbi at the cost of an out
>better than a no rbi but not an out (ie a walk)?

>paul

A statistic that is often given on TV and radio is the batter's average
with men in scoring position.  I think this is as good a ruler as any.

--
Doug Bowman
Emory University, Atlanta, GA

UUCP: {rutgers,gatech}!emory!doug      

 
 
 

Statistics questions -RBI's got vs chances?

Post by Nelson » Sat, 16 Jul 1994 14:28:41

Quote:

>Being new to baseball (not an American) I am often impressed by all the
>stats the game produces (BP, OBP, SLG, RBI, HR etc.) But it seems to me,
>perhaps somewhat naively, that RBI's isn't really a true reflection of
>the ability to hit in runs. I know I often see flash on the screen the BP
>of someone with runners on base. But is there a way to measure RBI's
>gained versus chances - i.e. who is the better batter, someone who has 50
>RBI's but batted a run in 80% of the time he had the chance to do so, of
>someone with 80 RBI's but only had a 50% average in the same respect. The
>second guy had more chances but he didn't capitalize as well as the first
>guy.

Welcome, Laurence.  This is actually the same view, in more polished forms,
that many of us advocate here on the net.  Jump right in!

===============================================================================
GO CALIFORNIA ANGELS!
===============================================================================

 
 
 

Statistics questions -RBI's got vs chances?

Post by Laurence Ch » Sun, 17 Jul 1994 01:13:52


Quote:


>>Being new to baseball (not an American) I am often impressed by all the
>>stats the game produces (BP, OBP, SLG, RBI, HR etc.) But it seems to me,
>>perhaps somewhat naively, that RBI's isn't really a true reflection of
>>the ability to hit in runs. I know I often see flash on the screen the BP
>>of someone with runners on base. But is there a way to measure RBI's
>>gained versus chances - i.e. who is the better batter, someone who has 50
>>RBI's but batted a run in 80% of the time he had the chance to do so, of
>>someone with 80 RBI's but only had a 50% average in the same respect. The
>>second guy had more chances but he didn't capitalize as well as the first
>>guy.

>Welcome, Laurence.  This is actually the same view, in more polished forms,
>that many of us advocate here on the net.  Jump right in!

OK I will! The one stat I see (and it has been mentioned in this thread
is) BA with men in scoring positions. And rightly so, the question is,
what constitutes a man in scoring position. In the All Star game clearly
Gwynn on 1B was in scoring position since he scored! I guess this is when
it becomes complicated.
A home run will score anyone.
A fly ball will score someone on 3rd if there are < 2 out
etc. etc.

I guess that is what makes this game so fascinating for the statisticians.
Still I think the raw RBI number is not something that should be looked
at too carefully though better players will have higher numbers because
1) they can hit 2) they are given the opportunity with batters ahead of
them whose role in life is to get on base. It is hard to see how a 1B
would ever get the RBI lead in a season.

+========================================================+

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Statistics questions -RBI's got vs chances?

Post by Nelson » Sun, 17 Jul 1994 08:55:22

Quote:

>OK I will! The one stat I see (and it has been mentioned in this thread
>is) BA with men in scoring positions. And rightly so, the question is,
>what constitutes a man in scoring position. In the All Star game clearly
>Gwynn on 1B was in scoring position since he scored! I guess this is when
>it becomes complicated.
>A home run will score anyone.
>A fly ball will score someone on 3rd if there are < 2 out
>etc. etc.

The common usage of the term "scoring position" is a player on 2nd or 3rd base,
since that usually means that a single will score the player.

(BTW, BA with men in scoring position is usually also not considered very
important by people who feel that RBI totals are misleading, because of the
small sample size and the random fluctuation that comes with it.)

===============================================================================
GO CALIFORNIA ANGELS!
===============================================================================

 
 
 

Statistics questions -RBI's got vs chances?

Post by Kokope » Sun, 17 Jul 1994 14:00:13

Quote:

>I have seen a proposal here of "Expected runs saved" in which you
>subtract number of runs allowed from runs expected for each situation
>(my apologies to whomever did that, it's been a while), but it
>seems pretty complicated in that you need lots of situational data.

We could use "Earned runs prevented," even though I don't especially
like Linear Weights. :)

ERA does fail to show the effectiveness of a reliever. Personally,
ERPT would work better, as would a tighter save rule - You shouldn't
get the save UNLESS you actually have the tying run on base or in the
batter's box.  Also, if you put yourself into a save situation, you
shouldn't get the save. The rule seems too lax, and it's making good
relief pitchers look insanely good, mediocre relievers great, and Lee
Smith the majors save leader. Not that I am complaining about that -
His saves are the only thing keeping me in the race for the roto league
title.

Quote:
>paul

--
Dylan Wilbanks, Environ. Con : Owner, The Mighty Platypuses of Boulder |
major, U of Colorado, Boulder: Clip .sig for 20% off your next woof!   |
PO Box 1143, Boulder, CO     : Rockies season ticket location (say hi) |
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Statistics questions -RBI's got vs chances?

Post by Mike Jon » Mon, 18 Jul 1994 02:13:33

Quote:

>ERA does fail to show the effectiveness of a reliever. Personally,
>ERPT would work better, as would a tighter save rule - You shouldn't
>get the save UNLESS you actually have the tying run on base or in the
>batter's box.

This is almost true. The tying run can be on deck, or you can pitch
the last inning with a three-run lead (or pitch three innings
effectively).

Quote:
>Also, if you put yourself into a save situation, you
>shouldn't get the save. The rule seems too lax, and it's making good

This is already the case. The save situation must exist when the
pitcher enters the game. If a pitcher comes in with 1 out in the 9th
and a 3-run lead, bases empty, he's not eligible for a save even if he
lets the first guy he faces reach base.


I see great things in baseball. It's our game--the American game. It will
take our people out-of-doors, fill them with oxygen, give them a larger
physical stoicism. Tend to relieve us from being a nervous, dyspeptic set.
Repair these losses, and be a blessing to us.
        - Walt Whitman

 
 
 

Statistics questions -RBI's got vs chances?

Post by David M. Ta » Wed, 20 Jul 1994 00:21:41

Quote:

>A statistic that is often given on TV and radio is the batter's average
>with men in scoring position.  I think this is as good a ruler as any.

There are two serious problems with BA/SP as an indicator of RBI ability.
The first is sample size: in order to be reasonably sure that you've
captured a player's true ability plus or minus 10 points of BA, you need
to have seen 8000 at bats.  If you're willing to settle for +/- 20 points,
2000 at bats will do.  Over several seasons, you can get a pretty good idea
of a hitter's overall ability, because he'll get those 2000 at bats.  But
it takes twice as long to accumulate PAs with runners on base, and 4 times
as long for runners in scoring position.  By the time a player has amassed
2000 PA with RISP, he's not the same player anymore that he was when he
started.

In an individual season, a player like Joe Carter might bat as many as 400
times with men on base.  The standard deviation of his batting average over
those 400 PAs is more than 20 points; if he hits .278, you can't be confident
of anything beyond the fact that his true ability is probably somewhere
between .240 and .320.  For other players, with fewer PA with men on base,
the problem is even worse.  And this model (all PAs identical) will tend to
UNDERestimate the variance, making the true spread of possible "true" values
even wider.

The second problem with situational batting average as a measure of RBI
ability is that there doesn't seem to be any *ability* to hit well with
men on base (or in scoring position) that is distinct from a general ability
to hit well.  The evidence for this is in the distribution across all players
of the *difference* between overall BA and situational BA.  In any particular
year, this distribution looks just like you would expect it to look if you
had selected the "situational" PAs by flipping coins, rather than by looking
at a particular kind of situation, with a slight overall shift for the league
as a whole.  (This shift, up for RISP and down for LIPS, seems to indicate
that *pitching* is qualitatively different in those situations, but that
hitting isn't.)

Furthermore, the people who are at the top end of the situational batting
lists one season are at the bottom end the next season, and vice versa.
There's no *stability* from year to year, the way there is for overall BA
or HR rate or slugging average or walk rate or any of the other primary
offensive stats.  Again, this suggests that any apparent *ability* to hit
better (or worse) than your overall batting stats would suggest in particular
situations is an illusion induced by small samples.

The best approach for quantifying RBI ability is probably to keep track of
a given hitter's % of runners driven in from first (second, third) per PA
with runners on base, and HR rate.  Of course, to interpret these numbers,
you'd also have to normalize by number of outs consumed in the process...
Again, though, there are going to be serious small-sample problems here.
A typical hitter might not bat with a runner on third more than 50-100
times in a season, so that the standard error in his RBI% from third base
will be on the order of 4% - 6%, which is large compared to the range of
actual player performances.  What good does it do to know that (say) Fred
McGriff drives in (say) 27% of runners from third base, plus or minus 10%?

--

    Professor of Story Problems    |  And he swatteth one of three.
  Dept. of Industrial Engineering  |        --Darnell Coleridge,
     University of Pittsburgh      |          Rime of the Youthful Griffey

 
 
 

Statistics questions -RBI's got vs chances?

Post by Mark Pag » Tue, 02 Aug 1994 11:03:03

In addition to Mr. Tate's comments, one must realize that a hitter's RBI
ability is largely affected by the quality of his team's offense in
general.  A hitter who plays behind teammates with high on-base averages
gets more chances, sure, but if those teammates are also base-stealers, he
is likely to get better pitches to hit.  Similarly, if the teammates that
follow him in the line-up are better-than-average hitters, he will get good
pitches.  A dangerous hitter in a weak line-up will often be walked in a
clutch situation.  (Check Ralph Kiner's numbers when he was with Pitt.)
 
 
 

Statistics questions -RBI's got vs chances?

Post by Mike Jon » Tue, 02 Aug 1994 10:37:29

Quote:

>In addition to Mr. Tate's comments, one must realize that a hitter's RBI
>ability is largely affected by the quality of his team's offense in
>general.  A hitter who plays behind teammates with high on-base averages
>gets more chances, sure, but if those teammates are also base-stealers, he
>is likely to get better pitches to hit.  Similarly, if the teammates that
>follow him in the line-up are better-than-average hitters, he will get good
>pitches.  A dangerous hitter in a weak line-up will often be walked in a
>clutch situation.  (Check Ralph Kiner's numbers when he was with Pitt.)

Actually, there's no evidence to support either of these assertions.
Batting average in ABs where a steal is attemped is *markedly lower*
than in other ABs. I can't say whether the batters get better pitches
to hit, but whatever pitches they get they're not hitting them.
There's also no evidence for the "protection" theory. A good hitter
with lousy hitters behind him will generally get intentionally walked
a few extra times per year, but it doesn't seem to be the case that he
gets walked a lot more.


Most people wouldn't know music if it came up and bit them on the ass.
        -- Frank Zappa

 
 
 

Statistics questions -RBI's got vs chances?

Post by David M. Nieporen » Tue, 02 Aug 1994 11:50:40

Quote:

>In addition to Mr. Tate's comments, one must realize that a hitter's RBI
>ability is largely affected by the quality of his team's offense in
>general.  A hitter who plays behind teammates with high on-base averages
>gets more chances, sure, but if those teammates are also base-stealers, he
>is likely to get better pitches to hit.  Similarly, if the teammates that
>follow him in the line-up are better-than-average hitters, he will get good
>pitches.  A dangerous hitter in a weak line-up will often be walked in a
>clutch situation.  (Check Ralph Kiner's numbers when he was with Pitt.)

One must *not* realize it, because it isn't true.  The players who bat ahead of
and behind you do NOT
affect your performance.

There is no protection effect.

RBIs are affected by opportunities, and basestealing can lead to more
opportunities (by moving a guy from 1b to 2b), but there is NO evidence that
"he's going to get better pitches to hit."

There is also no evidence that people behind you get you "better pitches to
hit."  In fact, the reverse seems much more plausible.  (Except that there isn't
a lot of evidence for that theory either.)

People walk a lot because they are good at walking.  Not because they are
dangerous or not, and not because the people behidn them are dangerous or not.

--
David M. Nieporent



Orioles 1994:  MVP - Palmeiro, RotY - Hammonds, Cy - Mussina

 
 
 

Statistics questions -RBI's got vs chances?

Post by Scott Southwi » Tue, 02 Aug 1994 11:55:54



Quote:
>One must *not* realize it, because it isn't true.  The players who bat
>ahead off and behind you do NOT affect your performance.  There is no
>protection effect.

Wait--better than a FAQ--can we just all put this in our .sigs? I
never want to read about protection again, and since I don't read
sig-files, that should take care of it... :>

yrs,
Scotty


   The players who bat ahead off and behind you do NOT affect your
            performance.  There is no protection effect.