In article <mssC5xB3I.2CG@netcom.com> mss@netcom.com (Mark Singer) writes: >In article <1993Apr22.175131.7396@pts.mot.com> ep502dn@pts.mot.com writes: >>In article 7G4@netcom.com, mss@netcom.com (Mark Singer) writes: > >>>During spring training I made a similarly innoncent-looking comment  >>>about clutch hitting on this bb and the flames were flying.  "no such >>>thing as clutch hitting" they (the SDCN's) all screamed.  I assumed >>>they also meant there was no such thing as any kind of clutch performance, >>>given their comments.  I'm still licking the wounds, but I do have >>>a rebuttal planned.  :)    (gotta do my homework, as they say) >> [some deletions] >>       Rather they showed, quite convincingly, that >>	past clutch performance has never been able to predict FUTURE >>	clutch performance. > >I'm sure *you* are convinced, Dave.  Apparently so is Tony Perez. >I, however, am not. > > >I believe at the time of the Sabo plate appearance that Juan Samuel >was on the bench available for pinch-hit duty.  Over the past four >seasons: > >		Non-Clutch			Clutch	  >		AB	H	BA		AB	H	BA > >Sabo		1539	452	.294		259	59	.228 >Samuel		1564	383	.245		278	83	.299	 > >I do *not* claim that this is a complete statistical analysis that >proves the existence of clutch hitting, or compelling testimony that >Samuel would have gotten a base hit.  I'm sure there is something wrong >with the sample size, or that the basic assumption that clutch >performance is random invalidates any conclusions from this limited >application.  Or something or other.  I don't pretend to understand >statistical analysis. >  Well, we agree on the last part.:-)  One of the basic things you need to  have in a statistic to be able to predict a player's performance on it in the future is for there to be a correlation from year to year.  A  player's batting average is correlated fairly well from year to year. A player's ability to walk or infielder's Defensive Average are correlated better.  That is to say, given their past performance in those statistics we can have a pretty good handle on how they'll do next year.  Put in  some simple information about aging and you can do even better.  One of  the basic problems with something like "clutch" batting average - overall batting average is that the correlation from year to year is almost zero.  Adding to the sample size doesn't seem to help much.  As a counterexample to  what you showed, consider the following two players from 1984-1987:                 Non-Clutch                      Clutch                AB      H       BA              AB      H       BA   Maldonado      1060    260     .245            254     78      .307 Lemon          1643    457     .278            256     57      .223  If you had had these two players in 1988, by your logic, in those "clutch" situations, you'd bat Maldonado for Lemon in a blink of an eye.  Well, in  1988, Maldonado hit .267 in "non-clutch" and .190 in "clutch", while Lemon hit .254 in "non-clutch" and .313 in "clutch".  Before you accuse me of  completely cooking the data, there were 96 players who had 25+ "clutch" at bats every year from 1984-1988 (according to Elias).  As a simple measure of clutchness, let's just look at clutch BA-non-clutch BA. If you use  '84-'87 to predict '88 for those 96 players, you'd find that 27 of the 96 were below league average in that measure both in '84-87 and in '88, 26 were above league average in both periods and the other 43 were  above in one and below in the other.  If you were just flipping coins, you'd expect to get 24 above/below in both and 48 that switched.  The difference between the observed results and the coin flip experiment is not statisically significant.  BTW, correlating players' _overall_ batting average from '84-'87 with '88 gives a correlation coefficient of 0.59, which is significant at something better than the 99.9% confidence level.  Correlating their (clutch-non-clutch BA) for the same period gives a correlation of  0.088, significant at no level of any interest.  > > >>       Everyone would agree (I hope) that a grand  >>	slam in the bottom of the ninth when your team is down by three >>	is a VERY clutch hit.  There is just no way to predict who is more >>	likely to get the clutch hit based on past performance (hitting in >>	"clutch" situations). >> > >If you say so, Dave.  No way.           >  Actually, it's technically incorrect to say that we can't predict future clutch performance.  It's more correct to say that we can't predict future clutch performance with any skill.  Harold