THE TWO POLICE DEPARTMENTS COMPARED WERE THOSE OF CITIES HETEROGENEOUS IN POPULATION (300,000) AND ECONOMIC BASE AND WITH A SUBSTANTIAL NONWHITE POPULATION. THE MOST IMPORTANT DIFFERENCE WAS THAT ONE OF THE POLICE DEPARTMENTS WAS HIGHLY PROFESSIONALIZED WHILE THE OTHER WAS NOT. IT WAS FOUND THAT A PROFESSIONALIZED POLICE DEPARTMENT TENDED TO EXPOSE A HIGHER PROPORTION OF JUVENILES TO THE POSSIBILITY OF COURT ACTION. IN THE PROFESSIONAL POLICE DEPARTMENT THE ORGANIZATIONAL SETTING WAS HIGHLY CENTRALIZED AND ALL JUVENILE OFFENDERS WERE PROCESSED IN THE HEADQUARTERS' JUVENILE BUREAU. IN CONTRAST, THE OTHER POLICE DEPARTMENT WAS HIGHLY DECENTRALIZED, AND OFFICERS TREATED JUVENILES PRIMARILY ON THE BASIS OF JUDGMENT AND ONLY SECONDARILY APPLIED FORMAL RULES OR ORGANIZATION. THE PROFESSIONALIZED POLICE DEPARTMENT WAS IN EFFECT AN ARMY OF OCCUPATION ORGANIZED ALONG PARAMILITARY LINES, WHILE THE UNPROFESSIONAL DEPARTMENT WAS RECRUITED, ORGANIZED, AND LED IN A WAY THAT FELL CONSIDERABLY SHORT OF ORGANIZATION STANDARDS. THE RATE OF JUVENILE PROCESSING BY THE PROFESSIONAL DEPARTMENT FOR ALL OFFENSES WAS MORE THAN TWICE THE RATE OF THE NONPROFESSIONAL DEPARTMENT. HOWEVER, DECISIONS WITH RESPECT TO PROFESSIONALIZING BIG CITY POLICE FORCES SHOULD NOT BE MADE WITHOUT CONSIDERATION OF THEIR EFFECT ON THE JUSTICE METED OUT IN DISCRETIONARY CASES. ANOTHER IMPLICATION OF THE STUDY IS THAT TRAINING OF A POLICE FORCE APPARENTLY ALTERS THE MANNER IN WHICH JUVENILES ARE HANDLED AND THAT PROFESSIONAL NORMS MAKE POLICE LESS DISCRIMINATORY BUT MORE SEVERE. THE AGE OF THE FORCE MAY FURTHER CONTRIBUTE TO DIFFERENCES IN POLICE BEHAVIOR AS THE PROFESSIONAL DEPARTMENT STUDIED WAS YOUNG IN AGE OF MEMBERS AND ALSO YOUNG IN THAT IT HAD BEEN RECENTLY REORGANIZED ALONG PROFESSIONAL LINES. (MJW)