Calculating Bridge Tournaments

Problem 5. Artificial Adjusted Scores

Description of the problem

Sometimes, due to an irregularity, a table has not been able to score a normal result on the board. The pairs are instead awarded artificial adjusted scores.
These scores will usually be given in %, where 60% and 40% are the most frequent, but 50% or any other number can also occur.
We are not concerned here with the result for the pairs getting the artificial score, as it is the director who immediately determines this result. There are some considerations in these matters too, but they are dealt with in another chapter.

We are concerned here with the effect that the ‘drop-out’ score will have on the rest of the field.

Solutions

1) Mitchell

The normal way this problem was resolved in the old times managed to retain integer results : to the normal scores are added the number of tables who did not obtain a normal result on the board.

The artificial score has been awarded with 9 MP. This is only a temporary score, used for two reasons :

• The total of 90 should temporarily remain unchanged for purpose of checking.
• The scores for both sides need not balance. When manually calculating match-points, we usually award 50%, and then correct the final total.

This is actually not a bad way of manually calculating a small tournament.

2) Mitchell-Neuberg

There is no reason why the Neuberg formula should not be used to solve this problem. There should be no difference between a board that has been fouled and played ‘on the other side’, and a board where one or more tables have received an artificial score.
The WBF has produced guidelines stating that the Neuberg formula should be used in this instance. The Mitchell 1 system is therefor out of official use.

3) Ascherman

In the Ascherman system, the (adapted) Neuberg formula, is of course used.

4) Cross-IMPs, Butler, Bastille

There are no real problems in this category.

Last Modified : 1996-09-12