THE UNIFIED DELINQUENCY INTERVENTION SERVICES (UDIS) PROGRAM, BEGUN IN CHICAGO IN OCTOBER 1974, PROVIDES INTERVENTION FOR JUVENILES WHO HAD BEEN ADJUDICATED SO OFTEN, OR FOR AN OFFENSE SO SEVERE, THAT THEY WOULD OTHERWISE HAVE BEEN COMMITTED TO THE COOK COUNTY JUVENILE DIVISION OF THE DEPARTMENT OF CORRECTIONS (DOC). AN EVALUATION WAS CARRIED OUT THAT COMPARED POLICE, COURT, AND INTERVENTION RECORDS OF 191 MALE DELINQUENTS ASSIGNED TO UDIS, 159 MALE DELINQUENTS ASSIGNED TO THE DOC JUVENILE INSTITUTIONS DURING THE SAME TIME PERIOD, AND 142 MALE DELINQUENTS ASSIGNED TO THE DOC JUVENILE INSTITUTION DURING THE 21 MONTHS PRECEDING THE ESTABLISHMENT OF UDIS. THE STUDY FOUND THAT SIGNIFICANT REDUCTIONS IN THE INCIDENCE OF OFFENSES -- AS HIGH AS TWO-THIRDS OF THE PREINTERVENTION RATE -- CAN BE ACHEIVED, EVEN WITH THE MOST CHRONIC, SERIOUS DELINQUENTS IN COOK COUNTY, THROUGH THE USE OF ENERGETIC CORRECTIONAL INTERVENTION. THE RECIDIVISM ANALYSIS DID NOT MAKE A CASE FOR THE OVERALL SUPERIORITY OF EITHER UDIS OF DOC. DOC LED IN REDUCING THE INCIDENCE OF OFFENSES, WHILE UDIS LED IN REDUCING THE SERIOUSNESS OF THE OFFENSES THAT CONTINUED TO BE COMMITTED. PROGRAM COMPONENTS, STUDY RESULTS, AND IMPLICATIONS FOR INTERVENTION ARE SUMMARIZED. SIGNIFICANT TABULAR DATA ARE PROVIDED. FOR THE COMPLETE REPORT, SEE NCJ-45072. (DAS)