What do you open when your hand qualifies for either 1 NT or one heart/spade?

A hand like this:

 

S)  A Q 7 5 4
H)  K Q 4
D)  9 7
C)  A J 6

 

Here you have a good five-card spade suit, but also a balanced hand of 16 high-card points.  Modern bidding standards allow either choice - 1NT or 1 spade.  Experts do not agree on the best practice.

Some say you should not open notrump with a worthless doubleton, such as this diamond suit.  Some proscribe other constraints.  There is one expert who says you should always open 1NT - no exceptions.  Determined to find the best practice, recently I studied hundreds of random deals, and here is what I discovered.

Opening 1NT with a five-card major in your hand produces better results on average than opening the major, even though you will often play in a notrump contract instead of the suit when the partnership has a 5-3 fit. 

The only special requirement to achieve this notrump advantage is for the responder to use the Stayman convention following a 1NT opener in order to find 4-4 and 5-4 fits.

Additionally, holding a worthless doubleton is not a deterrent to notrump.  To the contrary, you should come out ahead 63 times per 100 deals by opening 1NT with the type of hand shown above.

StdAm21 accepts either choice, but now recommends 1NT wherever your hand has a five-card suit (any suit), 5-3-3-2 distribution, and 16 to 18 points. 

Most of the bridge world has not yet discovered this advantage, so thanks to Bridge Snaps you now have a  leg up!