To decrease the number of crimes in city Y, the city' s Police Commissioner proposed taking some police officers from low-crime districts of the city and moving them to high-crime districts of the city
His proposal is based on city Y crime data that show that the number of crimes in any district of the city decreases when additional police officers are moved into that district
Districts of the city from which police officers are removed do not experience significant crime increases shortly after the removal of those officers.