Single Winner X-IMPS
My apologies, this has probably been discussed before and feel free to send me a link to some learned arguments. My club runs a X-IMP pairs championship and does not, the last few years, play single winner movements. best 6 scores out of a possible 12 sessions.
I gather this is down to the random swings, I've never been wholly satisfied with this argument though. You've got limited competition between the E/W and N/S pairs this way, and although we randomise the draw, there's some number of pairs with stationary seating rights (for a variety of good reasons), who almost form their own section. My own feeling is that arrow switching would represent the lesser evil, but I've never seen the issues examined rigorously. Any views?
Comments
The Young Chelsea has run an IMP pairs game every Friday for more than 40 years, originally Butler but now Cross-IMPs, and has always arrow-switched it in the same way as its matchpointed games because it always has single winner rankings. A couple of vocal members object to this because of the greater element of chance, depending on which direction you happen to play, but I think most members accept this in exchange for having a bit of variety of format. In any case, in most games there are other randomising factors that may outweigh this, such as when the number of tables exceeds the number of rounds or when strong/weak players are not spread evenly around the field.
In the case of your event, it seems to me that one such factor when having six out of twelve results count, is that some games will be higher-scoring than others.
Cross-IMP pairs is inherently less balanced than matchpointed pairs because many boards won't give opportunities to score more than a trivial number of IMPs. If you're playing those boards against stronger players, and the swingier boards against weaker players, you have an advantage.
I don't think it's possible to do much to counteract that effect in the movement, and it's likely to be a larger effect than things like arrow-switch imbalances.
Imps-Pairs is inherently of high volatility. For this reason, if no other, I think that discarding sessions is a way to resort some fairness. You all have a chance to pick up good sessions throughout the season and to throw aware the disasters, which might well have been little to do with you. Getting a vulnerable grand bid against you Imps pretty much destroys the session.