Thank you for your comment.
I agree that you allow responder to have more that 2 Spades the result will be different. But than you have some ways to describe
this hands with immediate support. I strongly believe in "support
with support, but this is another subject of discussions.
Based on my simulation of 1000 hands 1NT is better than 2S in
387 instances . 2S is better than 1NT in 248 instances.
This includes any positive result, not only 1NT or 2S.
It is more complicated to make a conclusion when both 1NT and
2S failed.
Thank you Kit,
I understand why 17 HCP is problem after 2NT rebid.
If the rebid of 2NT (When you play 15-17 HCP) is 18-19 HCP
the responder has the same problem with 6 HCP.
Should he/she bids 3NT or Pass.
18-6 HCP makes 3NT 36%.
19-6 HCP makes ...
I believe that with 8 HCP you should pass 1 NT.
With 9 HCP you should try for game. In this case the opener
knows you are inviting with 9 HCP and this facilitates his/her
decision.
Some people like to play 3NT with 16-8 HCP non fit.
I think ...