pescetom, on 2019-November-05, 07:51, said:
I did find a mention that Richard Pavlicek had done such analysis and concluded that opening 1NT was a clear winner with 5 hearts and a slight loser with 5 spades (no indication about scoring system or other assumptions). I can't find that on the RP site, although I did find this sobering
1NT vs 2S comparison instead.
This analysis (or my analysis of this analysis) is amazing. If my sums are right opening 1NT is a massive loser.
First what I read a single line to say - eg the top line - is that with the given distribution, 1NT wins (ie is the better open) and 2
♠ goes off 19.54 percent of 30302 cases, while 2
♠ makes on 42.94%+37.52% of 30202. Agreed? The website says that the figures are for where there are no overtricks in either contract.
Now assuming the shape you are concerned with in the choice of whether to open 1NT or 1
♠ is the 5{332} and you don't open 1NT on more extreme shapes, you can eliminate those other shapes.
Multiply each percentage by the number of cases to give the effective frequency result, add the columns, and you get a total of 1NT winning on 8.7% of hands and 2
♠ winning on 91.3% of hands.
That's a huge difference in a matchpoint scenario. I can't believe it would be that different for a 1
♥ open, as the play is the same, but of course opponents could intervene with a 1
♠ bid.