When to blow the whistle?
 

I am referencing the end of the Indiana-Illinois game. Illinois player goes up for a layup with 2.5 seconds left, Indiana player swats it horizontally out of bounds. I noticed the official blew his whistle (thus stopping the clock with .9sec) before the ball hit the ground.

It didn't matter in this game. I slowed down the tape and estimate that the ball hit the ground with .7 seconds left, which would have still been enough to hit the game-winning layup.

My question: if the ball is clearly headed out of bounds with no chance of a player returning it inbounds, should you whistle right away or wait until the ball is dead from hitting OOB?

I often see that sort of thing too. But, it isn't correct. The ball is not OOB until it touches something that is OOB....and only then should the whistle be blown.

This.

I never blow the whistle till the ball touches OOB. And I'd say maybe 35% of the time, some kid makes a pretty sweet save I wasn't anticipating.

I work with people all the time who just blow it when it's obviously going to WIND UP out of bounds, and it negates those very same save opportunities (or even more pedestrian ones).

The other thing is does is stop the clock before it should be stopped.