Newsgroups: rec.sport.baseball

In rec.sport.baseball, dtate+@pitt.edu (David M Tate) writes:

> >> >This seems like it would be pretty easy to measure -- if someone did
> >> >compute the correlation between OPP OBA/SLG and ERA, you could see
> >> >what pitchers had better ERAs than their OPP OBA/SLG suggested, and
> >> >see if this was consistent from year to year.
> >
> >Isn't this the "Clutch Pitching Index" from Total Baseball?
> 
> Not quite.  CPI uses an estimate of "expected runs" which is computed from
> opposing at-bats, hits, walks, and HBP.  This estimate is almost certainly
> a linear regression fit, since that's the only mathematical model Thorn and
> Palmer seem to have heard of.

Excuse me for being statistically dense here, but what exactly is the
difference between an estimate of expected runs computed from a linear
regression fit of opposing at-bats, hits, walks, and HBP, versus the originally
stipulated expected runs based on what "their OPP OBA/SLG suggested"?  Did you
have in mind a better use for opponent OBA and SLG than a linear regression
fit?  Perhaps some sort of RC-like stat?

If you mean that CPI's expected run estimate really used only raw hit totals,
and did not break down into singles, doubles, triples, and homeruns, then I
agree it is about as worthless as their Fielding Runs measure.

Your comments about the weirdness of top listings of CPI all time and single
reason records don't seem especially damning of the way CPI is computed,
either:

> most of the guys are unknowns.
> ...
> Funny thing, though: remember those all-time leaders I posted a minute ago?
> None of them appears more than 2 or 3 times among the top 100 seasons of all
> time.  Can you imagine a list of the all-time batting champs not including
> the players who show up on the top single-season list, or the all-time HR
> list not including the guys who were tops in the single-season list?  This
> sure looks to me like a "luckiest all-time pitchers" list.

This sounds to me like a damnation of the idea of clutch pitching.  First of
all, even if it did exist, I would not be at all surprised to learn that the
people best at it weren't particularly famous otherwise.  If I look at the top
20 or so ERA leaders, I get the feeling I should be looking at guys who simply
pitched well, not those who gave up bundles of hits and were consistently
"clutch" enough to strand them.  The latter sorts of pitchers I would not
expect to have great ERA's - more likely, they were mediocre ERA pitchers whose
"clutch" ability saved them being completely miserable.

Furthermore, if CPI measured "clutch" ability perfectly, but the measured
ability didn't exist (or was random), wouldn't I expect the top seasons of all
time to have little to do with the all time leaders?  The top seasons of all
time would belong to those very lucky for a year, and chances are, they would
have averaged out over a career.  The career leaders would be those who
happened to have long careers and who happened to score somewhat positive in
CPI more often than not.

-----------------------------------------------------------------------------
Marc "Dave" Sabatella		Disclaimer: OPS is not the One True Statistic
marc@hpmonk.fc.hp.com		that makes all others obsolete
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"Mmmm - po-ta-to chips!" - John Stuart Mill
Newsgroups: rec.sport.baseball