Breaking Tiebreakers

Posté par northlecale le 14 novembre 2016

Tiebreakers are not as unimportant as some people might wish them to be. Unless you’re using something like GoDraw, your pairing will be influenced by the tiebreakers which have been chosen by the tournament director. In other words, it is not just at the close of the event that the tiebreakers come into play. The EGF has a page which describes its current policy on tiebreakers - http://eurogofed.org/egf/toursysrules.htm - these date from 2007. This page is not as clear as it might be, and at times is offering some bad advice, but it is relatively useful all the same.

In a recent competition the following criteria were used

Swiss Score, Direct Comparison, SOS-2 – SOS-1, and SOS.

This is an unusual choice, but we can see where it came from. On the EGF’s page we have

If only one tiebreaker is used, then these tiebreakers are recommended:

  • Number of Board Wins.
  • Direct Comparison.
  • SOS-2.
  • SOS-1.
  • SOS.
  • Rating.
  • Previous Order.
  • Lottery.

What the organiser missed is

Recommended Order of Equal Players or Tiebreakers

  • This general order of priority is recommended:
  • Playing more rounds.
  • Playing playoff rounds, possibly with short thinking times.
  • Having equal players.
  • Using tiebreakers.
  • If only one tiebreaker is used, then the recommended order of priority is given by the list of tiebreakers that may be used.
  • Only one of SOS-2, SOS-1, or SOS may be used.
  • If more than one tiebreaker is used in a relative order of priority, then this is given by the relative order in the list of tiebreakers that may be used.

What he might have been further mislead by

Recommended Usage of Tiebreakers

  • Number of Board Wins: It can be applied only in a team tournament. There it is highly meaningful and should be the first tiebreaker.
  • Direct Comparison: Provided it can be applied at all, it is very meaningful because it might be interpreted as an already performed knockout playoff among the tied players. So, for the final results, generally it should be the first or even the only tiebreaker.
  • SOS-2, SOS-1, SOS: They should be used only in McMahon or Swiss. They express a mixture of opponents’ strength, statistical noise, and pairing luck. Their apparent numerical precision is greater than their true significance. Therefore they must be used with care. Application for the final results is doubtful while application for making pairings is reasonable. SOS-2 filters more noise than SOS-1 than SOS; more noise can be filtered in more rounds more easily.

Direct Comparison is a total devil if we try to use it to break ties between more than 1 player, in which case it is not at all a play-off game but an imagination which has run wild. SOS is much better suited to Swiss and McMahon pairings as it is considering the actual tournament performance, and not just extrapolating from 1 game.

An advice he was not given is that Direct Comparison should not be used in pairings, it should only be used at the end of the event in tiebreaking. It should never be used in making the pairings. It was then all rather unfortunate that this system was chosen. We have to consider why it was chosen.

  1. It was chosen because the TD studied the 2007 page and tried to apply it.
  2. It was chosen because the EGF does not validate or rubber stamp championship tournament systems
  3. It was chosen because nobody was brusque enough, or competent enough, to dispute it

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