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Zar points, useful or waste of energy


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The Zar Points are not as accurate as other simpler methods. That's my conclusion from analyzing 700K double dummy deals (downloaded from GIB site a long time ago).

 

Numbers below are for deals with a 9-card fit. (Results are similar for 10/11-card fit.) Columns are: points, average tricks, average error, cumulative percentages of making 8 to 12 tricks, number of deals. Each unprotected honor in a short suit is treated as the next lower-ranked honor. Distributional points are counted for both hands.

 

4321-531

Pts Trks Err 8 9 10 11 12 Deals

24 9.1 0.93 96 76 34 5 0 31076

25 9.4 0.93 98 86 49 11 1 30373

26 9.8 0.93 99 92 64 21 2 28169

This is the baseline with Works and 5-3-1 distributional points for void-singleton-doubleton. On average 25 points make 9.4 tricks with an error of 0.93 trick. 49% deals make 10 tricks or more.

 

Zar

Pts Trks Err 8 9 10 11 12 Deals

50 9.1 0.94 96 76 33 05 0 21882

51 9.4 0.94 98 84 45 10 1 21732

52 9.6 0.93 99 89 56 14 1 20469

53 9.8 0.93 99 92 66 21 2 19836

On average 52 Zar points make 9.6 tricks with an error of 0.93 trick. 56% deals make 10 tricks or more. The average error is comparable to the baseline.

 

6421-531

Pts Trks Err 8 9 10 11 12 Deals

30 9.1 0.89 97 76 31 4 0 22832

31 9.3 0.89 98 84 43 7 0 22328

32 9.6 0.89 99 90 55 13 1 21607

33 9.8 0.87 99 94 67 20 2 20705

The plain 5-3-1 evaluation for void-singleton-doubleton is more accurate than Zar's (a+b)+(a-d). The average error drops below 0.9.

 

BUMRAP-531

Pts Trks Err 8 9 10 11 12 Deals

24 9.0 0.88 96 72 26 3 0 29724

25 9.3 0.89 98 84 42 7 0 29389

26 9.6 0.88 99 91 58 14 1 27907

Now let's turn to BUMRAP with A=4.5, K=3, Q=1.5, J=0.75 and T=0.25. 50% game is between 25 and 26 points. The average error is comparable to 6421-531. Since no bidding systems can communicate fractions of a point, the points in both hands are rounded to the nearest integers before they are added together.

 

5321-531

Pts Trks Err 8 9 10 11 12 Deals

26 9.1 0.89 97 76 31 4 0 27252

27 9.4 0.88 98 86 46 9 0 26679

28 9.7 0.88 99 92 60 16 1 25460

If one doesn't like dealing with fractions, a simple way is to count A as 5 points and the accuracy for a game decision is still comparable to BUMRAP. To make the point scale compatible to 4321-531, one can still count A as 4 points but compensate that by subtracting 1 point for an ace-less hand and adding 1/2/3 points for 2/3/4 aces. Results are the same except that the relevant point range for a game decision changes from 26-28 to 24-26.

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  • 3 months later...

The Zar Points are not as accurate as other simpler methods. That's my conclusion from analyzing 700K double dummy deals (downloaded from GIB site a long time ago).

 

Numbers below are for deals with a 9-card fit. (Results are similar for 10/11-card fit.) Columns are: points, average tricks, average error, cumulative percentages of making 8 to 12 tricks, number of deals. Each unprotected honor in a short suit is treated as the next lower-ranked honor. Distributional points are counted for both hands.

 

 

 

Apologies for the late reply. Times have been regrettably interesting.

 

I really appreciate you taking the time to post this. It seems like BUMRAP and TSP are about the same and that it's just a matter of calculational ease and preference.

 

Is this an analysis that you can run at will? As-in, could you run this analysis on the additional adjustments from the Darricades book if I posted them or messaged you?

 

His complete list of adjustments takes about 2 pages. I feel like I do most of these in my head anyway though. So I'm curious as to how much error reduction you get with each additional piece using the numbers he's assigned.

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