Scenario 1: The police officer stops 20 people pulling aside equal numbers of Black and white people. Of the 20 people stopped, the officer uses force against 8 of them. The police officer used force against stopped white people and stopped Black people at the same rate: 40%. But that's not the only scenario that can lead to that 40% number. Scenario 2: This time, of the 100 people the officer sees, he stops 50. But this time he is biased in whom he pulls aside...