pescetom, on 2020-May-10, 14:12, said:
I was taught to respond 2NT as 12-14 and 3NT as 18-19 (17+ over 1M).
Not sure what disadvantages this has compared to a two-way scheme, the advantage of clarity is obvious.
I would have said the advantages of going slow were fairly obvious also - eg what if responder has heart support and was planning to make a delayed raise of 3
♥ then start a cuebidding sequence? If the right spot is no-trumps, you can always show your strength later; if not, you get the extra room to find it.
A
poll was done on the 3NT bid at BW a couple of years ago - far and away the most popular option (45%) was a 15-17 that wasn't suitable for 1N, with 28% voting for 18-19 options, 12% saying never bid it, and 8% some form of minimum. Many of the voters / commenters who voted for it showing 18-19 said they'd still go the 2NT - 4NT route for suitable 18-19 hands.