The pick and roll from the defender's side: four players and one read

What the screen actually creates

A screen removes a defender's path rather than the defender himself, which means the advantage lasts only as long as it takes him to find another route. The genuine product of the screen is a moment in which two defenders must decide simultaneously how to divide two attackers between them. Any hesitation in that decision produces a gap, and the gap is what the offence is actually attacking rather than the screen itself.

This is why a screen against two defenders who have played together for a long time achieves much less than the same screen elsewhere. The action is therefore a test of communication conducted at speed, and the physical contact is only the mechanism that forces the test.

The coverages and what each concedes

Going under the screen concedes the shot from distance and protects the drive, which is the correct trade against a handler who cannot shoot reliably. Going over the screen concedes the drive and contests the shot, which requires the screener's defender to delay the handler while the chase happens. Switching removes the decision entirely and concedes a mismatch, placing a smaller defender on a larger attacker or the reverse.

Trapping with both defenders concedes a four-on-three behind the action, which is the most aggressive option and the most expensive when it fails. None of these is correct in general, and a defence that uses one exclusively is offering the offence a fixed answer to a question it asks repeatedly.

The screener's defender makes the decision

The defender guarding the screener is the only player who can see the whole action, since the handler's defender is occupied and moving. His position at the moment of the screen communicates the coverage, and the handler reads that position rather than waiting for the defence to declare. A defender standing at the level of the screen indicates a hedge or a trap, while one dropping toward the basket indicates a conservative coverage.

The handler's response follows directly, since a dropping defender concedes the pull-up shot and a hedging one concedes the pass to the roller. This is why the action resolves so quickly and why the handler who reads the big defender rather than his own defender makes better decisions.

What the other three players are doing

The three players away from the action determine whether any coverage is survivable, because they are responsible for the help behind it. A defence that sends help toward the roller has left a shooter, and the pass out of the action is the offence's reward for forcing that help. Offences therefore position their shooters to make that help as expensive as possible, spacing them where a rotation cannot cover two of them.

The screener's roll is aimed at the region where help must come from, which forces the decision rather than merely occupying space. The whole action is consequently a five-player sequence disguised as a two-player one, which is why it is so difficult to defend consistently.

The short roll and the decision it creates

When the defence traps the handler, the screener becomes free in the middle of the floor with the defence outnumbered behind him. Receiving the ball there gives him a decision rather than a shot, since two defenders are rotating toward him and two teammates are becoming open. The quality of that decision is what determines whether the trap was a good idea, which is why trapping depends on who the screener is.

A screener who makes the read quickly punishes the trap severely, and one who hesitates allows the rotation to recover and the possession to reset. Defences therefore choose their coverage partly on the passing ability of a player who may never shoot the ball at all.