From: jdd@engr.ucf.edu (Joseph Dumas)
Subject: Re: Tie breaks for 5 Swiss Systems
Organization: engineering, University of Central Florida, Orlando
Date: Fri, 11 Dec 1992 16:56:50 GMT

sloan@cis.uab.edu (Kenneth Sloan) writes:
>All of the tie-breaks in the USCF ORC are useful, and each has it's
>place.  Sometimes, the difference lies in how much computation you want
>to do, and when you want to do it.  For example, the Cumulative tie
>break is attractive in a large Swiss because it can be calculated easily
>by hand, and can be calculated *before* the last round (or...if you are
>doing it by hand, *during* the last round) - but it is inferior to
>Solkoff (and friends).

Yeah, cumulative bites.  It favors players who are paired down in early
rounds over those unlucky enough to get fed to masters/experts at the
beginning, even though overall quality of opposition may be about the
same (or even more difficult for the latter group).  I've lost out on
this one before (years ago)....  About the only advantage of this method
(besides the ease of hand calculation) is that it discourages the Swiss
Gambit ... you need wins in those first couple of rounds, not draws, to
build up a good cumulative total.  (Unless, of course, you plan on
winning outright with 4.5/5!)

>I believe that the fairest tie break is "average opponents' performance
>ratings".  But, this requires considerable computation.  You must
>calculate a performance rating for every player (well...every opponent
>of a player involved in any tie break) and then use these performance
>ratings to calculate tie break scores.  The last stage is just as
>complex (or just as simple) as Solkoff - but the preliminary performance
>rating calculations can be overwhelming (especially if you have some
>unrated players in the pool).  
>
Why not "average opponent's established ratings"?  If I beat an Expert
who just happened to be having a rotten tournament, should that be worth
more than beating a 1650 who was otherwise lucky (or playing above his
head) and had a good score (and performance rating) just this once?  Or
not?  I kinda favor the use of the established ratings....  Scenario I
just thought of:  I knock off a 2050 player, who then immediately drops
from the tourney as he feels he has no chance of taking first.  Do I
then get his performance rating based on only one game (the one he lost
to me)?  Hardly seems fair; if he had stayed and played he likely would
have won most of the rest of his games and improved his performance
rating, to my benefit.  But this was out of my control.  Of course, if
you want to use established ratings of opponents, how do you treat
unrateds?

Maybe the best way would be to use "average of opponent's
post-tournament ratings", whether established or provisional, as
computed by Ken's program.  Of course then you have to make sure your
input data is good ... what if players have participated in other events
recently and the points haven't been processed by USCF yet?  How do you
make sure that you have good "Pre-" ratings?  I'm getting in deeper and
deeper here ... this will be a problem anytime you use ratings,
performance or otherwise, that are calculated on-site.
>
>>Many players don't like Action chess or Five minute in playoff matches.
>>The lower rateds think fast chess favors the higher-rated. 
>
>Everything favors the higher-rated!  Life is unfair.  You could simply
>declare that the USCF cross-table printing order will prevail (by score,
>and by pre-event rating within score group)

True.  They're higher rated because (up to now at least) they have
performed better at chess than the others.  I think the argument would
be better phrased as "this type of playoff favors those who have played
a lot of/are good at speed chess."  It's the equivalent of saying, "You
guys tied in the marathon.  We'll have a tiebreaker 100-yard dash to
determine the winner."  Ability at the longer distance (or time control)
may not fully correlate with ability at the shorter one.  I guess it
would be better than flipping a coin, though.
>
>Some of these tie-breaks favor the low-rated player in a Swiss - see the
>ones marked(!).  So...time to take a poll: which of these tiebreaks is
>your favorite, and why?  Let's limit the situation to: 5 round Swiss
>with a very wide range of pre-event ratings.  In particular - given the
>information below, and using *any* tiebreak criteria you can think of -
>which two out of the five players in the 3.0 score group would you
>select to play in the championship quad?
>
>================================================================
>
>                      Birmingham City Championship
>                              29 June 1992
>                               Qualifier

(deleting all but the tied parties)

>        Name         Score   Hark  Solk   Cum  Skof  Aver  OPer   OCum  Son-B

>       Kenneth Sloan   3.0    4.0   9.5   9.0   4.0  1533  1711   26.0   5.00
>         R. W. Ellis   3.0    4.0   8.5   7.0   4.0  1610  1543   24.0   5.00
>       Keyvan Amouie   3.0    4.0   7.5   8.0   4.0  1595  1548   17.0   5.00
>    Walter Schaetzle   3.0    4.0   7.5   6.0   4.0  1534  1622   21.0   6.00
>   Michael J. DeVivo   3.0    4.0   6.5   7.0   4.0  1382  1476   20.0   5.00
>
>Player                   Prev Perf Post R01  R02  R03  R04  Score
>  2     Walter Schaetzle 1932 1734 1916 L012 W018 W004 W009  3.0
>  3        Kenneth Sloan 1777 1733 1777 W017 W010 W012 L001  3.0
>  4        Keyvan Amouie 1755 1795 1765 W018 W011 L002 W008  3.0
>  5    Michael J. DeVivo 1715 1582 1702 W019 L012 W011 W010  3.0
>  6          R. W. Ellis 1537 1810 1581 W008 L001 W019 W007  3.0
>
Well, my first preference for a tiebreak, in general, is one not shown
above (or generally ever used in chess tournaments), but is used, for
example, in the NFL to determine playoff spots:  Head-to-head record.
Or, in the case of this situation, "division record".  Unfortunately
there wasn't much interaction between the tied players.  Schaetzle
defeated Amouie to give them 1-0 and 0-1 division records respectively.
So S. is in and A. is out.  The other three are 0-0 so we have to pick
one of the three using some other method.  My preference here (given the
problem with knowing pre-event ratings with certainty) would be for
Harkness or Solkoff.  Harkness is still a tie anyway, so I would take
the player with the most Solkoff points among Sloan, Ellis, and DeVivo,
namely Sloan.  So the final quad would be composed of Gwin, Schaetzle,
Sloan, andthe defending champion (Therrell?)

Anybody got any reasons *not* to use head-to-head results as the first
tiebreaker?  (Besides that it got Florida into the SEC Championship Game
over a Georgia football team with a better overall record ;^)

Joe
-- 
    ---------->  Joe is jdd@engr.ucf.edu (Joseph Dumas) <----------
"How about a nice game of Chess?"
"No, let's play Global Thermonuclear War."
"Fine."
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