Tie-Break system - how are they used?

Running Chess Tournaments
1

Hi I’m a mother of three young scholastic players (Aged 5, 7 and 9), in almost all of the tournament we attend the tie-breaks used are (in order)

  1. Modified Median, 2. Solkoff, 3. Cumulative, and 4. Cumulative of Opposition.

Can anyone give me a short definition of each of this tie-break system, and how are they calculated?

I do understand that the TD must used this system to break ties, it’s impossible for them to foreseen the outcome of the tournament and they must buy the awards prior to the event. I just want a better understanding about this tie-break system. Any help please!

Thanks in advance,
Lara

2

Hey, Lara, good question.

First it would be foolish not to have you seek out the 5th edition of the USCF rulebook which any current active tournament director must have. Go to section 34 and read about tie-breaks to your heart’s content. The summaries I give below are general in scope and do not cover all situations. The point of tie-breaks is to determine who is the “best among equals” for non-divisible prizes like trophies (cash is divisible).

That said, the tiebreaks you mention are used in that order quite frequently throughout the U.S. and, I believe, are the standard at all Nationals.

The Modified Median calculation is to list your opponent’s scores in the tournament, drop the highest and the lowest, and sum the rest.

The Solkoff applies the same formula, except you do not drop the highest and lowest.

Cumulative sums up your scores at the end of each round (1 point for each win, .5 points for each draw, 0 points for each loss). It favors the player doing well early as that usually indicates he faced sterner opposition throughout. For example, two players with 3 points in a five round tournament had these results:
Player 1: Win, Win, Win, Loss, Loss
Player 2: Win, Loss, Win, Loss, Win
Player 1’s accumulated score at the end of each round: 1+2+3+3+3 = 12
Player 2’s accumulated score: 1 + 1 + 2 + 2 + 3 = 9
And thus player 1 in this example has higher Cumulative score over #2.

Cumulative of opposition: you add up the Cumulative score of each opponent of the tied players, and sum those numbers (for a five round event frequently in the 30s-40s).

Of course, computers pairing programs typically perform these tasks automatically.

I hope that helps.

3

Thank you bbentrup for your explanation. I don’t think I need to acquire the USCF Rulebook as I do not have aspiration to get the headache of TD’s. I salute you and other TD’s out there for the hard work.

Anyway, your explanation is more than enough. I only need a better understanding how this tie-break are used, and you explain them well. Like I said with my prior post, I have children playing scholastic chess, we have run (several times in fact) into situation that one of my kid lost or won a trophy due to a tie-break. I would like to better explain to them when they asked me why they did not win the trophy (well, kids never asked why they win, only when they don’t) :slight_smile: .

Thank you again,
Lara

4

Always glad to be of service :stuck_out_tongue:

5

This is actually just plain Median. For Modified Median, drop the lowest opponent for players tied with a >50% score. Drop the highest opponent for players tied with a <50% score. Drop both high and low for 50% scores.

Also, remember that it is the opponents’s adjusted score. So, unplayed rounds (byes, forfeits, & withdrawals) all count as 0.5 points for the opponents score.

Jeff

6

Okey, I now understood the explanation for the following: 1. Modified Median, 2. Solkoff, 3. Cumulative, and 4. Cumulative of Opposition from my previous post.

I was just reading the rules for the upcoming national scholastic in Orlando, the Tie-Breaks are as follows:

  1. Modified Median
  2. Solkoff
  3. Sonneborn-Berger
  4. Cumulative
  5. Kashdan
  6. Game result between tied players
  7. Most Blacks
  8. Coin flip

1, 2, & 4 were covered from my previous question. Correct me if I’m wrong, I think 6 - is Head-to-Head Result between tied players, 7 - the player with the most black wins, and 8 - “everyone knows what a coin flip is”.

[size=150]But what in the world is Sonneborn-Berger and Kashdan?[/size]

Thanks for any help.

7

Sonneborn-Berger is a RR tiebreak. Players in the tie are awarded the sum of the final results of all opponents based on how they performed against those opponents.

A player gets:

the final scores of all the players he defeated,
one-half of the final score of opponents with whom he drew, and
nothing from those to whom he lost.

This break isn’t (supposed to be) used in swiss-systems due to the fact that losses are discounted.

See rules 34F and 34E8.

The Kashdan is described in 34E7. I’ve never used it!

8

The reason S-B is used in round robins is that Solkoff never breaks the tie! Two players with the same score in a round robin will automatically have the same Solkoff. In fact, ironically, the better a player’s score, the worse his Solkoff.

For the same reason, Median and Modified Median usually won’t break round robin ties, either. And, of course, Cumulative is meaningless in a round robin.

Bill Smythe