Backswing determines Length of Shot
When I am playing in pro-ams the shot that I see most players having difficulty with is the 50 to 80 metres pitch shot that requires less than full swing.
Most players make a swing that is too long and then decelerate the clubhead through the impact zone.
This is the only way they can prevent hitting the ball too far over the green and as a consequence they become very inconsistent. This can cause striking behind the ball or a low thin driving type of shot.
For better results let the length of the backswing determine the distance the ball travels.
This means that the shorter the shot the shorter the backswing. The clubhead must always be accelerating through the impact zone.
This will result in more consistent shot making and greater distance control.