What is the main intention when setting a ball screen? Give the ball handler a chance to score. Of course there are other options but that is the main intention. The ball handler must be able to separate from the screen and make a read on whether or not to attack. If the attack is shut down then they must find the appropriate option to make a play.
In the video below Tim Springer breaks down the technique of attacking off the pick and roll. The footage is taken from a scoring camp that featured Danny Green from the San Antonio Spurs.