IN THE FIRST STUDY, DATA WERE COLLECTED FROM SUBJECT INTERVIEWS WITH AND CRIMINAL-HISTORY RECORDS OF 49 INCARCERATED MALE FELONS IN A MEDIUM-SECURITY CALIFORNIA PRISON. THE SECOND STUDY, BASED ON A SURVEY OF 624 MALES INCARCERATED IN 5 CALIFORNIA CORRECTIONAL FACILITIES, EXAMINED OFFENDER'S CRIMINAL ACTIVITIES, ARRESTS, CONVICTIONS, JUVENILE HISTORIES, FAMILY BACKGROUNDS, EMPLOYMENT, CRIME MOTIVES, AND PERCEPTIONS OF THE BENEFITS AND RISKS OF CRIMINAL ACTIVITY. THE THIRD STUDY ANALYZED 2 DATA SETS FOR 11,000 SUSPECTS ARRESTED ON FELONY CHARGES IN 4 CALIFORNIA COUNTIES IN 1973. IT FOCUSED ON THE RELATIONSHIP BETWEEN CRIMINAL RECORD AND CASE DISPOSITION, AS WELL AS POTENTIAL EFFECTS OF SENTENCING POLICY CHANGES ON CRIME RATES. THE FINAL STUDY, BASED ON A DATA FILE FOR 625 DEFENDANTS CONVICTED BETWEEN 1968 AND 1970 IN THE DENVER (COLO.) DISTRICT COURT, ESTIMATED PERCENTAGE REDUCTIONS IN CRIME COMMISSIONS THAT RESULT FROM ALTERNATIVE SCHEMES OF MANDATORY SENTENCING, AS WELL AS THE EFFECTS OF SUCH SCHEMES ON PRISON POPULATION SIZES. THIS SUMMARY REPORT PROVIDES DATA ON INDIVIDUAL OFFENSE RATES AND VARIATIONS BY PRIOR RECORD AND AGE, CRIME MOTIVATION, EXPECTED UTILITY OF CRIME, ATTITUDES TOWARD CRIME, SOCIAL STABILITY AND DRUG USE, CRIMINAL JUSTICE CONTACTS FOR HABITUAL OFFENDERS, AND ESTIMATIONS OF INCAPACITATION EFFECTS. IT IS FOUND THAT CHARACTERISTICS ASSOCIATED WITH HIGH CRIMINALITY LEVELS (E.G., JUVENILE RECORDS AND DRUG USE) ARE THE SAME CHARACTERISTICS ASSOCIATED WITH HIGH RECIDIVISM LEVELS. HIGH-RATE OFFENDERS CONSISTENTLY FAVOR CRIMINAL ACTIVITIES OVER LEGITIMATE EMPLOYMENT. AS THEY GET OLDER, CAREER OFFENDERS ARE INCARCERATED FOR INCREASINGLY EXTENDED PERIODS, AN INCAPACITATION EFFECT WHICH SUGGESTS SIGNIFICANT REDUCTIONS IN CRIME. HOWEVER, INCAPACITATION OF HABITUAL OFFENDERS WOULD INCREASE PRISON POPULATIONS. THE DATA SUGGEST THAT THE SYSTEM SHOULD CONCENTRATE INCAPACITATION EFFECTS ON YOUNG ADULTS ENTERING THE MOST ACTIVE PERIOD OF THEIR CAREER. TABULAR DATA BUT NO REFERENCES ARE INCLUDED. (DAG)