Matchpoints vs. IMPs: It does make a difference

I played my first bridge tournament over the weekend. This was with C., a new partner with whom I'd played exactly once before.

We first played an open pairs event on Saturday night. We came in fourth overall, and second in our division. Pretty good going.

Considering how well we were doing, we teamed up with another pair to play in a Swiss team event on Sunday. Eric, our club's resident expert, warned us that the scoring was different. The open pairs event was scored using match points, the same system that we use at our club games. The team event, on the other hand, would be scored using IMPs.

"What's the difference?," we asked him.

"Bid aggressively," he advised.

We shrugged it off. What on earth does bidding aggressively mean?

We paid for our indifference by getting our heads handed to us. Placing dead last after playing 48 boards over 7 hours is no fun.

"Does the scoring system really matter so much?," asked the wife when I told her that we came in last.

I tried to explain to her and as usual, in the process of explaining it to somebody, I really understand the impact of the scoring system now.

In matchpoints, which is how the open pairs event and club games are scored, you are essentially competing against everybody in the room. And what matters is your rank within the group, not the actual scores. So, there is no point in trying to make wild bids. Conversely, you play very carefully, trying to make as many overtricks as you can.

In IMPs, which is how the Swiss teams event was scored, you are competing against just one team. And what matters is the difference in the scores between yours and theirs. The upshot is that you do make wild bids, because the bonus for a game can easily swamp what you lose by not achieving a part score. To be exact about this: you make bids that have only a 30% chance of making whereas at matchpoints you make bids that have a 50% chance of making.

We played the Swiss teams event carefully and conservatively and got slaughtered. Even though Eric told us not to.

UPDATE: This article explains the difference between matchpoints and IMPs.