[palmergnaw]

Hi all,

I have a partner that is passionate about bridge and knows a lot about bidding and cardplay. Somehow she has missing learning much about scoring. I know the difference between matchpoints and IMPs but I'm finding it difficult to explain the difference to her without resorting to examples. Her bidding and play strategy is quite matchpoints-centric even when playing IMPs.

Does anyone have an elegant way of explaining the differences between these two scoring methods to someone who is not terribly sophisticated?

Thanks,
Paul

[paulg]

I wrote https://berwickbridg...winning-tactics for my club members to try and explain. Certainly the highlighted parts may help.

[nige1]

PaulG provides excellent advice on how tactics depend on scoring method

IMO ...

• MPs/BAM is more skillful because all boards are potentially equal and each trick is important.
• At aggregate or imps, the result of a match often completely depends on only one or two boards. For example, which way you finesse on the slam-hand.
• At teams (imp/vp), however, one sponsor can provide the livelihood of up to 5 professionals.

[palmergnaw]

Thanks guys, helpful stuff!

[FelicityR]

Making the contract as declarer is the primary consideration at IMPs, especially a game or slam. Similarly defeating the contract, especially a game or slam, is the primary consideration as a defender. Being a solid declarer or defender matters.

At MPs overtricks or extra defensive tricks matter. Having a bit of flair and a gambling spirit will sometimes pay dividends, in both the bidding and the play.

[AL78]

nige1, on 2020-April-10, 04:47, said:

Paul provides excellent advice.

MPs/BAM is more skilful because all boards are potentially equal and each trick is important.

At aggregate or imps, the result of a match often completely depends on only one or two boards. For example, which way you finesse on the slam-hand.

At teams (imp/vp), however, one sponsor can provide the livelihood of up to 5 professionals.

At duplicate, there is a lot of luck in both. One of the better players in my local club refers to duplicate as largely a crap shoot, and it is in the situations where the variance in standard around the room is high, or there is a huge bias in which way the good hands go (both happen at my local club). The former increases the luck factor by being dependant on which hands you play against which pair. You don't want to get the flat boards against weak pairs, and you don't want the hands requiring high skill against the top pairs. In the latter case, it is very difficult to generate matchpoints or imps if you spend most of the evening passing and following suit, and repeatedly get the thin games and slams bid against you that only one or two others find. I much prefer head-to-head teams, where your teammates have a chance at replicating what happens at your table (and vice versa), and you have direct influence over your opponents. At MPs, it is not quite accurate to say all boards are equal (only true in a mathematical sense), because the potential to get matchpoints on a board is dependant on the deal. On very flat boards, no-one is getting more than about 55% (unless someone blunders), whereas on boards where a double game swing is there, you can get anything from 0 to 100% depending on whether or not you hit the perfect outcome. One of the drawbacks of duplicate bridge is the lack of influence over your true opponents. I can't immediately think of any other games or sports where it happens to the extent it does at bridge.

[pescetom]

AL78, on 2020-April-11, 15:54, said:

One of the drawbacks of duplicate bridge is the lack of influence over your true opponents. I can't immediately think of any other games or sports where it happens to the extent it does at bridge.

In mass start events like marathon or cross country skiing you quite often never see your direct opponents until the prize ceremony, if you are competing for a category win rather than absolute. And often you will be busting a gut for no good reason as you have already lost or are miles ahead. Duplicate is straight forward in comparison.

This apart, you make many good points here.

[AL78]

pescetom, on 2020-April-12, 01:37, said:

In mass start events like marathon or cross country skiing you quite often never see your direct opponents until the prize ceremony, if you are competing for a category win rather than absolute. And often you will be busting a gut for no good reason as you have already lost or are miles ahead. Duplicate is straight forward in comparison.

This apart, you make many good points here.

I'm not directly familiar with marathons or cross country skiing, but it looks like there are some events where a competitor has no influence over their opponents. Cycling time trials have just come to mind.

I should add that I was not intending to imply duplicate was mostly luck, or make excuses for my own poor performance. Skill is obviously a big factor. The top pair in my club are regularly winning, but very occasionally, they finish below 50%. Their skill most of the time is enough to more than compensate for the run of the cards, but if they have an off day, they can significantly underperform and/or be subject to the wrong side of the random element.

[AL78]

palmergnaw, on 2020-April-10, 03:52, said:

Hi all,

I have a partner that is passionate about bridge and knows a lot about bidding and cardplay. Somehow she has missing learning much about scoring. I know the difference between matchpoints and IMPs but I'm finding it difficult to explain the difference to her without resorting to examples. Her bidding and play strategy is quite matchpoints-centric even when playing IMPs.

Does anyone have an elegant way of explaining the differences between these two scoring methods to someone who is not terribly sophisticated?

Thanks,
Paul

Does your partner play golf? If so, explain that MPs is analogous to match play, and IMPS is analogous to stroke play.

Otherwise, it is as has already been stated, at MPs, you have to get a better score than the pairs sitting the same way as you, it doesn't matter how big the differential. There are only three outcomes against any one pair, win, loss, draw, and the MPs are accumulated depending on each outcome. IMPS, the magnitude of the score matters, so you don't just want to get a better score, you want to get a much better score than your opponents at the other table playing the same cards as you. This greatly affects the tactics, for example, at MPs, a bidding strategy which gains 100 points four times and loses 1100 once is an excellent strategy (frequency of gain vs frequency of loss matters), but at IMPS it is terrible. This affects strategy in bidding games (thin games are bid more often at IMPS, to get +620 instead of +170), and sacrificing (don't go for +500 against +620 if there is a significant chance you will go for +800 or more). When playing the cards, safety plays are more important at IMPS, the goal is to maximise the chance of making the contract, even if that costs overtricks, because overtricks are worth little. At MPs, you go for the line which has a decent chance of making the most tricks (i.e. if suits break the most likely way), because overtricks might make the difference between a top and a below average score. When defending, at MPs, you want to play safe most of the time* to avoid giving declarer valuable overtricks, whereas at IMPS, you take a line which gives you a chance (even if it is small) of getting declarer down, even if doing so will mostly give overtricks away, because the gain for +50 is much greater than the cost of -600 and -630. At MPs, your goal may not be to get the contract down, it may be to hold declarer to a certain number of tricks.

*One notable exception is if you are on lead and can see declarer has the remaining tricks on the layout, or just needs to lose the lead once more to establish all the tricks (e.g. there is a long running side suit in dummy), you can make a lead of desperation hoping to find partner with a trick or establish a trick, and if you happen to lead from Kxxx into AQ, it doesn't matter, because declarer was never going to take that finesse, so it is zero cost.

[nige1]

Alt78 makes good points ...

AL78, on 2020-April-11, 15:54, said:

At duplicate, there is a lot of luck in both. One of the better players in my local club refers to duplicate as largely a crap shoot, and it is in the situations where the variance in standard around the room is high, or there is a huge bias in which way the good hands go (both happen at my local club). The former increases the luck factor by being dependant on which hands you play against which pair. You don't want to get the flat boards against weak pairs, and you don't want the hands requiring high skill against the top pairs. In the latter case, it is very difficult to generate matchpoints or imps if you spend most of the evening passing and following suit, and repeatedly get the thin games and slams bid against you that only one or two others find. I much prefer head-to-head teams, where your teammates have a chance at replicating what happens at your table (and vice versa), and you have direct influence over your opponents.

At pairs, against whom, you play which boards can be critical. (No matter what the scoring method: aggregate, imps, or MPS). In this respect, straight Mitchell movements are better than Arrow-switch or Howell movements. although the latter have other benefits.

AL78, on 2020-April-11, 15:54, said:

I much prefer head-to-head teams, where your teammates have a chance at replicating what happens at your table (and vice versa), and you have direct influence over your opponents.

As AL78 says, teams events do eliminate this bias, to some extent, (Again, no matter what the scoring method: aggregate, imps, or BAM). Although, in professional teams of 6, which boards the sponsor plays can be decisive.

AL78, on 2020-April-11, 15:54, said:

At MPs, it is not quite accurate to say all boards are equal (only true in a mathematical sense), because the potential to get matchpoints on a board is dependent on the deal. On very flat boards, no-one is getting more than about 55% (unless someone blunders), whereas on boards where a double game swing is there, you can get anything from 0 to 100% depending on whether or not you hit the perfect outcome ...

At aggregate/imps, being on the wrong side of a double-game swing -- or worse double-slam swing -- can be decisive. At MPs/BAM, a freak disaster is just another bottom -- recoverable with a good performance on run-of-the-mill boards..

[AL78]

nige1, on 2020-April-12, 07:59, said:

[size="2"]
At aggregate/imps, being on the wrong side of a double-game swing -- or worse double-slam swing -- can be decisive. At MPs/BAM, an unlucky disaster is just another bottom -- recoverable with a good performance on run-of-the-mill boards..

True, MP's heavily limits the maximum gain/loss on a board, so a bad board is more easily recoverable. Even so, I find at MPs, three or more boards of getting the rough end of the deal/it's only a bottom is near impossible to recover from, without playing near flawlessly on the rest of the boards, which I am not good enough to do (the best players in the room can, hence they frequently get 60+%).

[pilowsky]

palmergnaw, on 2020-April-10, 03:52, said:

Hi all,

I have a partner that is passionate about bridge and knows a lot about bidding and cardplay. Somehow she has missing learning much about scoring. I know the difference between matchpoints and IMPs but I'm finding it difficult to explain the difference to her without resorting to examples. Her bidding and play strategy is quite matchpoints-centric even when playing IMPs.

Does anyone have an elegant way of explaining the differences between these two scoring methods to someone who is not terribly sophisticated?

Thanks,
Paul

Hi Paul
As you know, I am just a beginner at bridge but I do know something about learning. To help someone that doesn't understand that there is a difference it is often helpful to start with some simple aphorisms to help them find their feet. Just knowing the differences is helpful for experts but not for a beginner.
Ron Karr from Palo Alto provides an excellent Table.
The main message I got was: be crafty and sneaky at IMPS but be bold and forthright at matchpoints.
Don't double at IMPS.
Try to make overtricks at matchpoints but make your contract at IMPS.
Bid the safest slam at IMPS. Bid the best slam at Matchpoints.
Partscores: don't be too aggressive at IMPS. At matchpoints try not to let them play below the 2 level.
In defense take risks to beat game at IMPS. At matchpoints avoid giving up overtricks.
It seems that two bad boards will destroy an entire session at IMPS but not at matchpoints: this is the main thing that I try to remember. Two -11's and you are gone.
What do the others think?

[AL78]

pilowsky, on 2020-April-12, 16:45, said:

Hi Paul
As you know, I am just a beginner at bridge but I do know something about learning. To help someone that doesn't understand that there is a difference it is often helpful to start with some simple aphorisms to help them find their feet. Just knowing the differences is helpful for experts but not for a beginner.
Ron Karr from Palo Alto provides an excellent Table.
The main message I got was: be crafty and sneaky at IMPS but be bold and forthright at matchpoints.
Don't double at IMPS.
Try to make overtricks at matchpoints but make your contract at IMPS.
Bid the safest slam at IMPS. Bid the best slam at Matchpoints.
Partscores: don't be too aggressive at IMPS. At matchpoints try not to let them play below the 2 level.
In defense take risks to beat game at IMPS. At matchpoints avoid giving up overtricks.
It seems that two bad boards will destroy an entire session at IMPS but not at matchpoints: this is the main thing that I try to remember. Two -11's and you are gone.
What do the others think?

I don't agree with not doubling at IMPs. If the opponents have bid stupidly aggressively against you then you should punish them for it, and if they are sacrificing you need to get as big a penalty out of them as possible to compensate for the game they have talked you out of. Perhaps what you mean is don't double tight partscores into game, be confident you can get them at least two down before doubling. At MPs, tight doubles are sometimes necessary as the only chance to avoid a bad board. For example, you bid to 3H, the opponents bid 3S, they are vulnerable. If the room is allowed to play in 3H making, you have to double 3S to stand any chance of a decent score, 3SX= is the same bottom as 3S=, and 3S-1 undoubled will also be a bottom, but 3SX-1 will get you a top. Doubling at IMPs in that situation would be a reckless high risk low reward.

To do well at either form of scoring, defend like a boss.

[pilowsky]

Thank you. What I mean is that as a beginner I need very clear guidelines at the start to help me. Later as I get to understand better I can grasp the nuances and make better judgements. Your points are very helpful in that regard. I have also doubled in exactly the situation that you mention.

[palmergnaw]

pilowsky, on 2020-April-12, 16:45, said:

Hi Paul
As you know, I am just a beginner at bridge but I do know something about learning. To help someone that doesn't understand that there is a difference it is often helpful to start with some simple aphorisms to help them find their feet. Just knowing the differences is helpful for experts but not for a beginner.
Ron Karr from Palo Alto provides an excellent Table.
The main message I got was: be crafty and sneaky at IMPS but be bold and forthright at matchpoints.
Don't double at IMPS.
Try to make overtricks at matchpoints but make your contract at IMPS.
Bid the safest slam at IMPS. Bid the best slam at Matchpoints.
Partscores: don't be too aggressive at IMPS. At matchpoints try not to let them play below the 2 level.
In defense take risks to beat game at IMPS. At matchpoints avoid giving up overtricks.
It seems that two bad boards will destroy an entire session at IMPS but not at matchpoints: this is the main thing that I try to remember. Two -11's and you are gone.
What do the others think?

Thanks Paul, I think you're onto something here! I'll just qualify the doubling part and give it to my partner.

[pescetom]

AL78, on 2020-April-12, 05:28, said:

I'm not directly familiar with marathons or cross country skiing, but it looks like there are some events where a competitor has no influence over their opponents. Cycling time trials have just come to mind.

Done plenty of those too and you are right of course, although at top level one may receive information about time gap relative to a competitor who started earlier - downhill skiing is similar in this respect. Also climbing competitions and some types of motor sports such as rally.