what ODR is this?

[Fluffy]

♠AKQJ

♥9xx

♦8xx

♣Jxx

 

all vul, dealer south, match points

 

ps-(1♣)-X-(3♣)

X -(ps)-3♠-(4♣)

??

 

 

my original intention was to double first then bid 3♠ wich seemed to me to show an invitational hand with 4 spades, in retrospect 3♠ the round before would had saved me from the decision now, feel free to comment on it.

[cloa513]

You`d need only slightly better for 4 ♠ say with a doubleton diamond or doubleton heart and 4 clubs.

[gnasher]

I think that double-3♥-3♠ would just show 4-4 in spades and diamonds - that is, it shows a different shape rather than a different strength. I'd just bid 3♠ over 3♣. If partner has a singleton club and four spades, he'll probably raise anyway.

 

After dbl-3♠, what can partner have? With a 4342 shape I'd expect him to bid 3♦, and I can't believe that he's 4333.

 

Maybe he has five bad spades. xxxxx KQJ KQxx x is a pretty good game on the bidding, and that looks more like a takeout duble of 1♣ than an overcall. I bid 4♠.

[Fluffy]

I think you are right Andy, double was wrong.

 

partner had

 

♠108xxx

♥AQxx

♦Kxxx

♣-

 

 

opponents have a mirror 2335, ♥K offside, but ♦A onside, its pretty hard to defeat 4♠ since wichever red suit might serve as discard for the other.

[mike777]

nonexpert here but

 

I hope those forum players who play ODR will explain it, the very best they can.

 

In other words....define it.....:)

--------------

 

 

So if you ask what is ODR ...i go to chart....:)

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Trust me forums love charts.........

 

 

If this borderline no problem...but chart please :)

[peachy]

I bid 3S over 3C. Dbl tends to show either both majors or neither major, and ofc some values. With one major, just bid it. In that auction, I don't have to worry what my next bid/call should be.

[Ant590]

I hope those forum players who play ODR will explain it, the very best they can.

 

In other words....define it.....:)

It's not a convention but a method of hand evaluation called Offence to Defence Ratio. It's designed to help you decide in these high-level decisions how your x-count fits in with the variety of possible hands that have x points, with a view to deciding when to bid on, when to double, and when to make a (forcing) pass.

 

An extreme example is: with a 10-count with all the points in the opponents suits you want to double their contract, but with a 10-count will all the points in your suits you want to bid on. A range of different factors favour bidding on (high ODR), to doubling (low ODR).

 

See "partnership bidding at bridge" by Robson and Segal (an authorized free version is available at http://bridgewithdan.com/systems/), page 23 onwards for a better definition.

[pooltuna]

nonexpert here but

 

I hope those forum players who play ODR will explain it, the very best they can.

 

In other words....define it.....:P

--------------

 

 

So if you ask what is ODR ...i go to chart....:)

-------

 

 

Trust me forums love charts.........

 

 

If this borderline no problem...but chart please :)

If you want numbers I suspect something like "total points/IMPs/MPs scored as declaring side"/"total points/IMPs/MPs scored as defending side".

[gwnn]

positives:

 

-length in our suits

-shortness in their suits

-4 or 5 small cards in your RHO's suit provided we have 9 or 10 trumps (but this is also a + on defence)

-queens and jacks in our suits (or kings if we have a very big fit)

-concentration of values

-note that aces are almost always completely neutral

 

negatives are obviously the opposite of those above...

 

This is sort of copied from the Robson Segal book because that's where I learned of the concept. Nowadays I don't think much about these things and it is generally instinctive. It is a mildly useful term on discussing competitive bidding since your ODR is usually what decides whether you need to act as opposed to HCP or ZAR or whatever.

 

Note that if you want to treat the book as Gospel, the fact is that some of the ideas does not work nearly as well as the book make them sound... They tend to underestimate the perils of passing with values when you have no fit for p initially. Also the way they describe takeout x's vs 4S is naive somewhat, you need to double on slightly less distribution also.

[helene_t]

If you want numbers I suspect something like "total points/IMPs/MPs scored as declaring side"/"total points/IMPs/MPs scored as defending side".

I think it should be

[#tricks made if declaring] - [#tricks made if defending]

 

It is beyond me why people persist in talking about the ratio. It's the difference that matters.

[pooltuna]

If you want numbers I suspect something like "total points/IMPs/MPs scored as declaring side"/"total points/IMPs/MPs scored as defending side".

I think it should be

[#tricks made if declaring] - [#tricks made if defending]

 

It is beyond me why people persist in talking about the ratio. It's the difference that matters.

for an actual usable number the difference is absurd. Not that I am sure mine is any better :)

[helene_t]

Well IMP(dcl)/IMP(def) is surely absurd since

 

+10 / -10 = +1/-1 = -10/+10 = -1.

 

Same with total points.

 

As for tricks(dcl)/tricks(def) it is a little less absurd. But still not good:

 

Suppose you improve your hand with a card that is worth an extra trick both in offense and defense. What impact should that have on the ODR? It could turn a cheap sac into an even cheaper phantom sac, but it could also turn a phantom sac into a make. What will actually happen to the ratio is that it will go down because ODR is usually >1. Unless you have a very defensive hand. This makes no sense. W.r.t. (O-D), the extra card will be neutral. Makes a lot more sense.

 

Then the question of whether the tricks we are talking about are tricks taken by your own hand or tricks taken by the partnership. The latter makes no sense because we want to be able to express the ODR of a single hand, sometimes in the context of some knowledge about the other three hands, but generally without knowing the complete deal. But suppose you have a defensive hand (maybe with a void in partner's 8-card suit). Now we transfer a card worth a trick in either offense or defense from your hand to partner's hand. That would mean that both hands' ODR would go up, so both partners should now bid more aggressively, as a consequence of a change that has no effect! Again, w.r.t. (O-D), such a transfer is neutral as it should be.

 

ODR also gives you division-by-zero issues. OK, the expected number of tricks is rarely exactly zero, but it is absurd to say that 1/0.1 is the same as 10/1 for the purpose of competitive bidding decisions.

 

O-D is meaningful. As a first approximation, use the LOTT so O=#trumps and D=(#cards in the enemy trump suit). Then you make adjustments, i.e. add shortages that are worth more in offense than in defense, subtract honors that are worth more in defense than offense, and v/v.