A new method of calculating the result of Duplicate Pairs Tournaments :


The Ascherman system is an alternative way of scoring the results in a Pairs' Tournament. It's ease of use and internal logic should make it the only way of scoring in the next century.

Let me first describe the Ascherman system on its own. In stead of counting 0..2..4..6, we count 1..3..5..7. That's all : one point extra. I consider the 'bottom' still to be 0 (happily unobtainable), the 'top' to be 2 times the number of results (sadly unobtainable). The percentage is still this result devide by the top.You will never get either 0% or 100%, but the bigger the field, the closer these percentages can be approached. In a field of 10 tables, the solo top gets 19/20 = 95%. In a field of 100 tables, this will be : 199/200 = 99.5%.

This is exacty equal to the principle that is the basis of the Neuberg formula which should be in official use in all tournaments. In that formula too, a result is awarded more or less points depending on the number of results it has been compared to. The most normal use of the Neuberg formula is when dealing with 'fouled boards'.Consider the following example : (first using the classical method of scoring)In a tournament of 100 tables, a board which has been misduplicated has been played at 10 tables. The best of these 10 results would get a score of 18/18, which would be corrected to 189 using the Neuberg formula :

(18+1)/10*100-1 = 189

The best of the 90 tables would get 178, which is transposed to:

178+1/90*100-1 = 197.89

whereas the solo top in the big field would normally score 198 (100 tables). Indeed you have probably played better if you are the best player out of 100, than as the best player of 90, and certainly better than the best of a mere 10 tables.

In the Ascherman system, this becomes:

The top of 100 tables is 199/200 = 99.5%
The top in the small subfield of 10 tables = 19/20 = 95% = 190/200.
The top in the larger subfield of 90 tables = 179/180 = 99.44% = 198.89/200.
As you can see, these results are always one higher than the 'classical' ones.

It should be immediately clear that the Ascherman system will produce exactly the same result as the classical system (which I have been calling the Mitchell system).

The advantage of this system is then that the very difficult 'Neuberg' formula now becomes very easy to use, intuitively so.

This system has been in everyday use in my club in Antwerp, the Royal Squeeze Bridge Club, and in several other clubs in Flanders, since january 1989.

It has been presented to the WBF and several of its leading directors, who have yet to find flaws in it, although they seem hesitant to start actively promoting the system.The Ascherman system is elegantly complemented by another invention of mine : a way of calculating the results of a board on which 'split-scores' have been awarded, such that the NS and EW pairs do get complementary results (on all tables except the one with the split-scores of course).

Although I develloped the system on my own, particularly while programming my results program 'BRIGITTE', I do not claim to have made an original invention. In fact, I have discovered that a very similar system was described by a Dutch Bridge League official, Ir. Wim Ascherman, in the early 1950's.

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Last Modified : 1996-02-16

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