You can put your astronomy textbooks away. We have an answer for you.

Short answer: Roll Gravity is a player’s ability to pressure the defense through their screening and rolling, forcing defensive help the same way a great shooter might on the perimeter.

If Clint Capela is rolling hard to the rim and has a step or two on his man, the defense will either collapse or face dire consequences.

If Isaiah Thomas is rolling hard to the rim, we won’t see the same effect on the defense.

Our Roll Gravity grades also incorporate a component that evaluates how a player’s screening ability assists their team in generating scoring abilities. Not all screeners execute screens the same.

Picking and popping also counts. And in some specific cases, we’ll see guards grade out well in Roll Gravity who are on teams who will use them to set screens for others (sometimes real, sometimes just for show) and flash to the 3-point line. This grade captures that as well.