THE JUVENILE JUSTICE ACT OF 1977 MOVES WASHINGTON'S JUVENILE JUSTICE SYSTEM AWAY FROM A TREATMENT MODEL OF JUVENILE CRIME AND TOWARD A JUSTICE MODEL. THE LAW LIMITS THE DISCRETION OF PROSECUTORS IN FILING CHARGES AGAINST JUVENILES; MANDATES THAT AGE, OFFENSE, AND (IN SOME CASES) USE OF A WEAPON OR BODILY HARM TO THE VICTIM BE USED TO CLASSIFY CONVICTED JUVENILES AS SERIOUS, MINOR, OR MIDDLE OFFENDERS; ESTABLISHES THE GENERAL TYPE OF SENTENCE (COMMUNITY SUPERVISION, INSTITUTIONAL) FOR EACH TYPE OF OFFENDER; AND REQUIRES THE JUVENILE CORRECTIONS AGENCY TO DEVELOP DISPOSITIONAL STANDARDS, WHICH DEFINE A SENTENCING POLICY BASED ON AGE, OFFENSE, AND PAST RECORD OF THE OFFENDER. A COMPUTER SIMULATION OF WASHINGTON'S JUVENILE JUSTICE SYSTEM UNDER THE NEW LAW WAS DEVELOPED AND USED TO ASSESS THE IMPACT OF FIVE ALTERNATIVE SETS OF DISPOSITIONAL STANDARDS ON THE SYSTEM. THE SIMULATION MADE IT POSSIBLE TO DETERMINE HOW EACH SET OF STANDARDS WOULD AFFECT THE NUMBER OF ADMISSIONS TO INSTITUTIONS AND THE LENGTH OF STAY. ADMINISTRATORS WERE ABLE TO DISCOVER HOW, BY VARYING DISPOSITIONAL STANDARDS, IT IS POSSIBLE TO CONTROL THE RATE OF FLOW OF JUVENILES THROUGH THE CORRECTIONS SYSTEM WITHIN LIMITS SET BY THE LAW. FULL DETAILS OF THE SIMULATION PROCESS AND THE DISPOSITIONAL STANDARDS ARE PRESENTED. PLANS TO BASE FUTURE SIMULATIONS ON DATA ON JUVENILE COURT REFERRALS MADE UNDER THE NEW LAW ARE NOTED. (EARLY SIMULATIONS HAD TO BE CONDUCTED WITH DATA ON REFERRALS MADE PRIOR TO IMPLEMENTING THE NEW LAW.) COMPUTER REPORTS PREPARED IN THE COURSE OF THE SIMULATION PROJECT ARE APPENDED. (LKM)