[blml] 60% session in IMPs

[David Burn]

[JP]

We know that over 28 boards, 60% is 49 imps.

[DALB]

I am not sure how we know. Pairs (matchpoints, for the benighted) and IMPs
are different games, to the extent that comparisons between them at this
level of granularity (x matchpoints = y IMPs) appear to me to be
meaningless. In theory, it is possible to score 100% in a 24-board pairs
game by making a trick more than everyone else in the same contract; if you
translated this to a match, you would win by 24 IMPs. Similarly, it is
possible to score 50% in a pairs game by making a trick more than everyone
else in the same contract on twelve of the boards, and going thirteen down
in 7NT redoubled on the other twelve. If you did that in a match, you would
lose by 276 IMPs.

I have read various examples of the rationale for equating matchpoints to
IMPs, and I am not remotely convinced by any of it. Still, there are
compelling reasons why some figure needs to be arrived at. I have no
convincing arguments why the figure I pluck out of the air should be "10% of
a top = 2 IMPs" rather than the current (in England) 3 IMPs, but JP
apparently has. If I score 28 60% boards in a pairs tournament, that equates
to 56 IMPs at 2 IMPs a throw; not quite the 49 IMPs he quotes, but closer to
that than the 84 IMPs I would have scored at 3 IMPs a throw. I still
believe, though, that comparing scores achieved at pairs to scores achieved
at IMPs is to compare apples not with oranges, but with screwdrivers.

David Burn
London, England