Time to analyse ZAR Points Just another gimmick?
#1
Posted 2012-April-03, 01:29
ZAR Points is a statistically derived method for evaluating bridge hands. Zar Points (ZP) are based on high card points and distributional points.
1. Zar high card points (ZHP) are the sum of the traditional Milton Work or Charles Goren 4-3-2-1 scale and control values for the ace and king, 2 for an ace and 1 for a king.
2. Zar distribution points are the sum of the lengths of the two longest suits plus the difference between the longest suit and the shortest suit.
3. An opening hand requires 26 ZP and a responding hand needs 16 ZP.
4. Adjustments are then made for fit.
5. Once these adjustments have been made, a major suit game requires 52 ZP, a small slam requires 62 ZP and a grand slam requires 67.
Traditional methods allocate distributional points as follows
1. Long suit points = Add 1 point if the hand contains a 5-card suit. Add 1 point for each additional card in the long suit.
2. Void = 5 points (once a suit fit is found) (some prefer 3 points)
3. Singleton = 3 points (once a suit fit is found) (some prefer 2 points)
4. Doubleton = 1 point (once a suit fit is found)
SAYC, probably one of the most basic systems, advocates 13 HCP to open the bidding. The Rule of 20 says open the bidding if your HCP plus the number of cards in your two longest suits totals 20 or more.
ZAR Points made simple (paragraph 2 in the above article) for opening hands is to divide everything by 2 and open with 13 points as taught by Charles Goren.
So is this just another gimmick?
#3
Posted 2012-April-03, 07:47
gwnn, on 2012-April-03, 02:07, said:
I didnt know that ZAR Points had already spent so much time on the treadmill. Some of those threads go all the way back to 2004. What I enjoyed about this thread is that ZAR himself spent a lot of time in it defending his brainchild.
Thanks a zillion (or should that be a ZARllion?)
#4
Posted 2012-April-03, 07:52
#5
Posted 2012-April-03, 10:18
#6
Posted 2012-April-03, 17:48
KnR - 0.866
Zar - 0.865
Milton - 0.809
The maximum possible correlation would be 1, implying that with any given combined count the exact number of tricks you make double dummy is a given, which is clearly unachievable by any method, not least because you can't take fractions of tricks.
I still prefer to start with the basic Milton and use various factors for upgrading/downgrading, which methods like Zar and KnR are an attempt to quantify. However, they don't distinguish between the "opening" hand and the "responding" hand, while short suits tend to be more useful in the "responding" hand.
(Edit: "Regression" -> "Linear regression" for clarification.)
#7
Posted 2012-April-04, 00:57
Statto, on 2012-April-03, 17:48, said:
Could you add LTC just so we know how horrible it really is?
-- Bertrand Russell
#8
Posted 2012-April-04, 01:46
you have no idea what simple basic ltc is.......
in any case please note we all agree it is not perfect...... and your style is so much better....
#9
Posted 2012-April-04, 08:20
TWOferBRIDGE
"imo by far in bridge the least understood concept is how to bid over a jump-shift
( 1M-1NT!-3m-?? )." ....Justin Lall
" Did someone mention relays? " .... Zelandakh
K-Rex to Mikeh : " Sometimes you drive me nuts " .
#10
Posted 2012-April-04, 12:00
I reject count methods that (a) marginalize judgement in favor of formulas, and (b) take longer than 5 seconds to count a hand.
-gwnn
#11
Posted 2012-April-04, 14:32
mgoetze, on 2012-April-04, 00:57, said:
Basic LTC - 0.753
New LTC - 0.852
(New LTC counts a missing Ace as 1½ losers, a missing King as 1 loser, and a missing Queen as ½ loser, and subtracts the total from 25, with a minimum opening hand typically having about 7½ losers.)
(Bear in mind all these values are across all hands; there might be slightly better [or worse] correlation around the game and slam zone.)
#12
Posted 2012-April-07, 15:37
#13
Posted 2012-April-07, 15:51
fuburules3, on 2012-April-07, 15:37, said:
Depends on local regulations. I would suggest a prominent note in whatever place opps tend to look at first on the CC that your evaluation is not based on HCP, then try to give approximate HCP ranges in parentheses on the CC.
-- Bertrand Russell
#14
Posted 2012-April-07, 15:53
fuburules3, on 2012-April-07, 15:37, said:
No.
You have the obligaton, to make sure, that your opponents understand your alert,
assuming, reasonable base knowledge.
And it is certainly not reasonable to require them to know what ZAR points are,
and I doubt you can give a prober alert in less than 1 min.
With kind regards
Marlowe
Uwe Gebhardt (P_Marlowe)
#15
Posted 2012-April-07, 16:21
A=5
K=4
Q=3
J=2
T=1
It leads to some screwy (imo) evaluations...like Axx Axxx Axxx Ax has only 20 Banzai points which qualifies this hand as a weak NT!
But Klinger gave numerous deals where if both partners used Banzai points, it correctly determined whether the partnership should bid to 3N.
Sorry if this is a hijack, but this evaluation runs counter to Zar points which awards a higher relative value to aces and kings. I guess you want to know in advance whether partner has a balanced or unbalanced hand.
#16
Posted 2012-April-07, 17:31
#17
Posted 2012-April-07, 19:07
bed
#18
Posted 2012-April-07, 21:22
straube, on 2012-April-07, 16:21, said:
...
Sorry if this is a hijack, but this evaluation runs counter to Zar points which awards a higher relative value to aces and kings. I guess you want to know in advance whether partner has a balanced or unbalanced hand.
Zar points are entirely geared towards suit contracts. Banzai points are entirely geared towards NT contracts. It's not surprising that they run counter to each other.
However, the analysis that Banzai points are based on (which was done by Richard Cowen in 1987) is flawed because it is based on the number of winners in each suit in isolation without taking account of the overall number of losers. To take an extreme case, KQJ10 in two suits opposite KQJ10 in the other two suits is judged as being worth 12 tricks in the analysis, when clearly with 4 Aces missing it is only worth 9 tricks, plus perhaps a bit for luck if opps don't manage to cash all 4.
I ran the linear regression analysis for NT contracts, restricting it to cases where both hands are balanced (5332/4432/4333 - 24% of all deals) and found that Banzai had a correlation of 0.900 compared with 0.912 for Milton. The caveat of course is that double dummy analysis is not ideal, as for one thing it grossly undervalues Queens, assuming that with a choice of finesse, possibly either way, or drop, you'll always get it right.
Thomas Andrews has done some research into this kind of stuff.
#19
Posted 2012-April-08, 01:25
So exactly how many different methods of hand evaluation are there?
Here is a list of the common ones that most players are familiar with.
1. Milton Work Point Count / Goren Point Count
2. Distributional Points
...a. Suit length points
...b. Suit shortness points
3. Control Count
4. Negative/Positive Features
5. Defensive/Attacking Values
6. Rule of 20
7. Rule of 19
8. Rule of 15
9. Suit Quality Test (considered useful for making an overcall)
10. Losing-Trick Count (LTC)
...a. Original
...b. LTC Refined
...c. New Losing Trick Count (NLTC)
11. Law of Total Tricks (LOTT)
12. Quick Tricks
13. Playing Tricks
These methods are all discussed in this article.
This thread contains a number of lesser known methods for hand evaluation:
14. Banzai Points click here and here.
15. Binky Points. I couldn't find a nice detailed reference here. Hopefully someone can help.
16. BUM-RAP I couldn't find a nice reference here either. Can someone help?
17. Danny Kleinman
18. ZAR Points
How many other methods of hand evaluation do you know about? To extend this list as far as possible will be a great reference source for others interested in these lesser known methods.
Thank you.
#20
Posted 2012-April-08, 03:26
32519, on 2012-April-08, 01:25, said:
It may be of academic interest, but if you spend the bulk of your time learning different numerical methods of hand evaluation rather than on other parts of the game, including non-numerical methods of hand evaluation, you will significantly hamper your rate of improvement at bridge.
All of these methods simply try and quantify how strong a hand is, and it is much better to work on picturing how the hand might fit with partner's and how it is affected by the opponents bidding. The ability to assess that improves with understanding the play of the hand and with practice.
In short, what jjbrr said. 4321 is a fine place to start, and the rest does not need to be converted to a number.
If you really want another method, I offer the 'warm fluffy' coefficient. Say you have a decision to make. You will know whether it's maximum or minimum and those decisions are easy. If it's in the middle you look at the hand and count the number of 'warm fluffies' you get when looking at it. If it's enough, you take the more aggressive action; if not you take the more conservative one. Put another way, work on your instincts and learn to trust them.