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ODR origins

#1 User is offline   Fluffy 

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Posted 2011-June-02, 14:27

I have got to know about the offensive/defensive ratio concept from many years on the forums, but I wonder where the term comes from, wouldn't surprise me it started on the "fought the law" book from Lawrence.
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#2 User is offline   JLOGIC 

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Posted 2011-June-02, 14:30

You think the term offense to defense ratio was invented a few years ago (or whenever fought the law was written)? Interesting.
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#3 User is offline   Fluffy 

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Posted 2011-June-02, 14:33

completelly uknown in spannish, not even a bad translation
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#4 User is offline   gnasher 

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Posted 2011-June-02, 14:41

It was discussed at length by Robson and Segal in 1993, 11 years before I Fought the Law was published.

I was vaguely aware of the phrase some time before that, but possibly only because I played at the same club as Segal and Robson.
... that would still not be conclusive proof, before someone wants to explain that to me as well as if I was a 5 year-old. - gwnn
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#5 User is offline   JLOGIC 

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Posted 2011-June-02, 14:44

View PostFluffy, on 2011-June-02, 14:33, said:

completelly uknown in spannish, not even a bad translation


No one has ever compared how good the offensive value of their hand is compared to the defensive value in a spanish speaking country? Am I wrong that ODR is not a formalized concept, that is simply all that it means? In that case, I cannot believe that you thought that it was "invented" by fought the law, maybe they formalized it in some way that I am unaware of, otherwise...lol.
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#6 User is offline   babalu1997 

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Posted 2011-June-02, 14:59

View PostJLOGIC, on 2011-June-02, 14:44, said:

No one has ever compared how good the offensive value of their hand is compared to the defensive value in a spanish speaking country? Am I wrong that ODR is not a formalized concept, that is simply all that it means? In that case, I cannot believe that you thought that it was "invented" by fought the law, maybe they formalized it in some way that I am unaware of, otherwise...lol.


perhaps not with that exact terminology, but edgar kaplan in the early 60s taught about the difference between quick tricks and defensive tricks, and even offered translation ruloes.

the more distributional the hand, the more offensive it is

plus all the discussion about neutral hands for offense/defense

if memory does not fail me some books by ron klinger discuss this issue too.

View PostFree, on 2011-May-10, 03:57, said:

Babalu just wanted a shoulder to cry on, is that too much to ask for?
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#7 User is offline   mgoetze 

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Posted 2011-June-03, 00:54

View Postbabalu1997, on 2011-June-02, 14:59, said:

perhaps not with that exact terminology, but edgar kaplan in the early 60s taught about the difference between quick tricks and defensive tricks, and even offered translation ruloes.


That is not quite what Robson and Segal talked about when they introduced ODR. Aces are "ODR-neutral" for them, and as for Kings, Queens, and Jacks, it depends whether they are in "our" suits or "their" suits.

Read up on it in their book, available from http://bridge.mgoetz...t/bbf.html#comp .
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#8 User is offline   babalu1997 

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Posted 2011-June-03, 09:04

View Postmgoetze, on 2011-June-03, 00:54, said:

That is not quite what Robson and Segal talked about when they introduced ODR. Aces are "ODR-neutral" for them, and as for Kings, Queens, and Jacks, it depends whether they are in "our" suits or "their" suits.

Read up on it in their book, available from http://bridge.mgoetz...t/bbf.html#comp .


Thanks, I do have that book. For Kaplan queens and jacks in the opps bid suit are assigned increased defense values dpending on their poaition.

But many authors before Robson and segal, have the tackled the topic of shifting hand valuation, with different terminology, you can even get references to it from Mollo's Declarer Play Technique. And, of course, from Lawrence's Complete book of hand valuation.

View PostFree, on 2011-May-10, 03:57, said:

Babalu just wanted a shoulder to cry on, is that too much to ask for?
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#9 User is offline   helene_t 

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Posted 2011-June-03, 12:28

R/S offered some argument why it should be O/R rather than O-D. I never understood this. To me, the difference (rather than the ratio) between the number of tricks I can take in offense and the number of tricks I can take in defense are what matters. Say that my O-D is 4 and p's is 2, then our combined O-D is six tricks and is lawful to bid 4 over 4 since if we make four tricks in defense we also make ten tricks in offense.

You can't use O/D in the same way. Oh well if the scale is exp(#tricks) rather than #tricks then I am cool with ratios but that probably isn't the idea.
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#10 User is offline   gwnn 

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Posted 2011-June-03, 12:40

I don't think they were very specific if it was O/D or O-D. They just said that your overall hand strength is not as important as the ratio. They don't speak about exact mathematical formulas or even mention any numbers at all.
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#11 User is offline   kenrexford 

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Posted 2011-June-03, 13:33

Sometimes I think OCD has more impact on bidding than is given credit or recognized.
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#12 User is offline   whereagles 

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Posted 2011-June-04, 05:23

Yes, R/S weren't too specific as whether it was O/D or O-D. The latter case is much more user-friendly and you can even cook up some rules for preempting from it, e.g.:

O-D = 5 --> you're ok for a 2-level preempt at R/R or G/G (4 for G/R, 6 for R/G)
O-D = 6 --> you're ok for a 3-level preempt at ...
etc...
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#13 User is offline   glen 

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Posted 2011-June-04, 08:23

Predating Segal & Robson, there was the concept of "Offensive Premium", which "determined how worthless the hand is on the defensive relative to its playing value".

In reference to Ken's post, OCD predates bidding, but bidding added the necessary structure.
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#14 User is offline   Zelandakh 

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Posted 2011-June-09, 05:17

In answer to the OP question I believe ODR comes from Andrew Robson - this one of his key skills as a bridge author and part of his success formula. As others have suggested differentiating between offensivee and defensive values has come up in various guises down the years. The oldest I can think of is from Culbertson, where his evaluation method (HTs) is essentially a rough guide to the defensive value of the hand but then when considering some bids he prefers to use playing tricks which is a rough guide to the offensive power of a hand. Naturally this is a long way from ODR though!

I think it is pretty irrelevant whether you count tricks, ratio features, or even use 2 different evaluation methods for offense against defence - what matters is that the evaluation provides a good basis for decision-making for both members of the partnership.
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