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Subject: Not meaningless - just not absolute

Author: Albert Silver

Date: 05:35:29 02/14/03

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On February 14, 2003 at 07:10:40, Rolf Tueschen wrote:

>Just to explain some basics for new readers, I show why the whole List is
>worthless. The rankings are by chance the way they are presented.
>
>Since only a few here have basic knowledge in statistics I explain the most
>apparet things.
>
>We are told that for instance the two first programs are seperated by 8 points.
>No matter Stefan get all the credits here for his first place. But is true that
>Shredder is stronger than Fritz?
>
>Here I must tell you that we simply don't know it. The SSDF pretend to know it,
>but it is NOT true. How can I say such things? Easy! Look at the deviations.
>These numbers with + or -. We see that most programs have an expected Elo number
>varying plus/mius of about 30 points! Note, that the Elo minus 5 is as probable
>as the fially given Elo for the ranking!
>
>If you then take a look at the Elo of the opponents in the far right you can see
>that even for the top programs the SSDF was unable to create equal conditions.
>Also this influence by different opponents makes the 8 numbers difference at the
>top meaningless.
>
>In sum we can say that the SSDF failed to show - exactly what they pretend to
>show - the differences between the actual top programs. The SSDF presents a new
>leader, but that is against its own results! So that the conclusion is allowed
>that SSDF makes deliberately their own new number 1!

Your comment that being number 1 in the list is not an absolute is completely
correct. The SSDF doesn't claim it is a statistical absolute either, which is
why they present the data: rating performance, number of games, AND the error
margin.


     THE SSDF RATING LIST 2003-02-13   90961 games played by  251 computers
                                           Rating   +     -  Games   Won  Oppo
                                           ------  ---   --- -----   ---  ----
   1 Shredder 7.0  256MB Athlon 1200 MHz     2768   33   -31   547   72%  2606
   2 Deep Fritz 7.0  256MB Athlon 1200 MHz   2760   29   -28   654   70%  2612
   3 Fritz 7.0 256MB Athlon 1200 MHz         2740   30   -29   574   64%  2635
   4 Chess Tiger 15.0  256MB Athlon 1200 MHz 2726   27   -26   704   64%  2623


If they present the error margin, doesn't this *clearly* mean that the result
may be off by that much? However, so far the current performance is 2768 SSDF
points. How many games does a human play to get their rating? I won't event
mention the ridiculously low requirement by FIDE to play only 9 games to get a
first rating. Suppose I had no rating and played 100 games against a 2000 Elo
player and I scored 75/100. My performance is 2200 exactly. Is it absolute? No,
there is a good margin of error, yet no one will question the rating and start
telling me I'm not rated 2200, I'm just rated anywhere between 2140 and 2260. I
see no difference. They had Shredder 7 play 547 games against other programs,
and presented the results PLUS the error margin. It *may* still be a fraction
weaker than Deep Fritz 7, but already it is clear that it performas better than
Chess Tiger 15 against other computers. But even if another 200 games changed
the top ratings to Shredder 7 = 2762 and DF7 = 2763 would anyone be so foolish
as to claim one program is actually any stronger?? I certainly would never think
of an opponent rated 10 points more as stronger. The fact that two such
different playing styles achieve almost identical performances shows how rich
and flexible chess is.

                                         Albert

>
>(Note please that this is not a political speech, however it is what statistics
>demands. The SSDF got this critic so often in the past but they still did't
>change their experimental setting.)
>
>Rolf Tueschen



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