What is the correct way to measure brace height?

 I have always measured mom from the deepest throat of the grip to the string...and  of course if it's a straight handle the bow you just measure from the string to the handle

Some bowyers have their own specs, but normally it's as Terry described.

Yeah, that's AMO but I measure to the back of the bow because  the throat usually doesn't meet the scale of the square.  Once it's where I want it I put a black sharpie ring around the shaft at the correct point and it's good to go.

That's with B50 and B55 strings.  Folks who use the low stretch strings probably don't need to watch it so close.

Great, Thanks y'all

When in doubt - start with 1/8th of the AMO length - deepest part of the grip to the string.