When you compare distributions of race for police departments and for the residents of the area they serve, you find disparity in many metropolitan areas. Jeremy Ashkenas and Haeyoun Park for the New York Times report, focusing on the higher percentage of white police officers.
Stacked bars show race distributions for residents (top) and the respective police department (bottom) for selected cities. A map for each area shows bubbles colored by amount of gap and sized by number of police officers. The darker the shade of green, the bigger the gap, so you see mostly green maps.