Combining Sessions with Different Tops

by David Stevenson

The problem is how to combine two sessions of a pairs event which has different tops, an example being given with 18 pairs all-play-all, which has a 16 top followed by a 14 top.

1. You could get a consistent average, and use Neuberg to achieve this.
2. You could add the scores together unfactored.
3. You could factor the lower set by higher top/lower top.
4. You could factor the lower set by higher total mps/lower total mps.
5. You could work each session out as a %age and add %ages.

All methods are legal.

EBU regs and current software require #1, which Max Bavin and Herman De Wael recommend.

The EBU Movements Manual by John Manning recommends #2. David Martin agrees for all-play-all. Max seems to think this might be acceptable if there is no computer available.

Both Max and John Manning disapprove of #3 and #4 [and presumable #5].

According to David Martin Haworth uses #1.

The Neuberg formula is [EBU version]

((M*E)+(E-A))/A

where M=actual MPs, E=largest no of scores on any board, A=actual no of scores on this board.

The ACBL version [based on half-match-points] is

(E/A)*(M+0.5)-0.5

which gets the same effective answers.

Herman recommends Ascherberg, which is not [as I was told by John Probst] a different method, but an all encompassing method that includes Neuberg but scores slightly differently.

It seems to me that all methods are legal, #2 is acceptable if there are no computers, but #1 seems best, and is used by EBU and Haworth software. OK?

Note that method #5 is definitely used and has the advantage that simple players prefer it as being clear and understandable. It presumably is equivalent to #3 or #4.

Editor's note:

• If you want to comment on this article, why not write direct to David Stevenson?
• I shall be pleased to hear from you!

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