police (2) Control (2) States (2) Strategy (2) Speeches, addresses, etc (2) Police (2) Lectures and lecturing (2) Field experiments (2) States (2) Number (2) Field experiments (2) police (2) test (1) secteur des services (1) recherche (1) analyse (1) étude de terrain (1) expérience scientifique (1) effet (1) ville (1) crime (1) abords (agglomération) (1) taux (1) Causes (1) Treatment (1) Cleaning (1) Telephone calls (1) Databases (1) Correspondence (1) Databases (1)