In swiss tournaments or knockout tournaments it's important to rank the players to the best of your ability before doing the pairings. This does indeed increase the chances of ending up with the best player at the end and the effect is not insignificant.
It's very easy to see this with knockout tournaments. Imagine a tennis tournament where the top 4 seeds played each other in the first and second round so that only 1 remains. For everyone else, the pairings would be much easier and every players chance of surviving till the final round has gone up dramatically. You would see players you never heard of in the semi-finals, etc. The same basic principles apply to swiss tournaments. You have much fairer tournament if you know in advance how strong each player is and can pair accordingly. This is not just to increase excitement, it's mathematically sound. In swiss pairings, you don't just select the players initially by strength, but when you make score groups you also rank the players by strength. If you have 10 players with 3 points, you don't play the best 2 players, you play the top 5 against the bottom 5 in the proper order. Otherwise, you will likely have the ridiculous situation where the best players is less likely to win this round that the weakest. Imagine these ratings for the 3 point group: 2500 2490 2300 2200 2100 2000 1900 1800 1700 1200 If you pair the 1700 vs the 1200 and the 2500 against the 2490, you have ridiculous situation where the the 1700 player is far more likely to advance than the 2500 player! Since the problem is recursive, you will now have a 1700 player in a group in which he probably does not belong and the 2500 player will be playing way down in the next round. It's not just a matter of fairness to these players, but to the ones who have to play them in later rounds. Some rulebooks that describe swiss tournaments will have some clause in them that tells you to estimate the rating of the players if you don't have an actual rating and that it should be the best estimate you can muster. So even if you are wrong, you should at least attempt to estimate the ratings of the players for pairing purposes. Don On Sun, May 8, 2011 at 2:22 PM, Nick Wedd <[email protected]> wrote: > In message <[email protected]>, Ingo Althöfer < > [email protected]> writes > > Hi Nick, >> >> thanks for the information. >> >> >> >KGS seems to use a sub-optimal pairing program: ... >>> >There are 12 participants. >>> >How can you pit, in a CH-system, four of the five >>> >strongest against each other in the very first round? >>> >>> It does not use any knowledge of the players' strengths. >>> >>> And if it did, it would _prefer_ to pair the stronger players against >>> each other, so as to obtain more information. >>> >> >> That might be good for sparring tournaments. >> However, in "title tournaments" a normal pairing >> scheme should be used, to get highest chances >> that the best participant wins. >> A normal scheme for such a goal would >> be to pair the upper half of the participants >> against the lower half in the first round. >> > > There are reasons for doing a pairing such as you describe. But I don't > believe that "highest chances that the best participant wins" is one of > them. Indeed, if that is your objective, such a pairing is pessimal. > > > Nick > -- > Nick Wedd [email protected] > _______________________________________________ > Computer-go mailing list > [email protected] > http://dvandva.org/cgi-bin/mailman/listinfo/computer-go >
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