This isn't meant to be comprehensive but as a reasonable framework for expansion.
Coach Daniel provides an outstanding terminology introduction.
Why screen? Defending screens is among the most difficult individual and team tasks required for successful basketball.
What are the major advantages of screening? Screening creates separation, exacts a physical toll on defenders, frequently informs mismatches, and punishes defenders/teams that communicate poorly. Screening has a core role in zone attack. In the NBA, a guard may get screened fifty times in a game.
Bone-jarring, concussion-inducing screen on Rondo. In slow motion, it looks as though Humphries puts a little shoulder into it (foul).
What are the major disadvantages of screening? Some players adopt a negative attitude about screening ('grunt work'), it creates technical challenges, requires patience, may interfere with spacing, and may lead to offensive fouls especially with bad technique (moving screens, back screens improperly sets).
Where can you set screens? You can set screens anywhere, but most commonly you see them at the top, elbow, and wing, and occasionally on the baseline. "Drag screens" can be particularly effective.
How do you set screens? As noted in previous posts, you can screen an area or screen the man (head hunt). Effective coaching provides GUIDANCE and PRIORITIES. For the most part, I teach players to screen the player, not an area. Sprint into the screen, add deception by taking an angle into the screen, set the screen at a proper angle, and protect yourself. I encourage girls to cross their arms with the dominant hand grasping the other wrist. You should be slightly bent at the knees and waist, with your feet wider than your shoulders. DO NOT throw a shoulder, elbows, backside, or leg into the defender. Our priority is setting LEGAL screens.
I favor the screener provide a hand signal that she is screening - this could include raising an open hand or putting the open hand across her chest. The ball handler can also 'request' a screen with a hand signal. After setting the screen, the screener can roll or pop, depending on the defender's reaction and the screeners skill set. Faking a screen and 'slipping' to the basket can create an outstanding opportunity for screeners.
How do you come off screens? Setting up your cut is critical. Misdirection is central to establishing separation. I often suggest players say, "wait, wait, wait" prior to cutting off the screen. Leaving too late is better than leaving too early. But when you go, you've got to go 'downhill', exploding off the screen. I like cutters to use their inside hand to 'turn' the screener into the play and assure no space for defenders to split the gap. This is quite 'unnatural' for players.
Can you share a drill you like? I like this drill I call "Indiana" as I adapted it from Bobby Knight.
It's easy to understand the challenges presented for defenses by the screen game.
