THIS STUDY IS AN ATTEMPT TO DEVELOP A PRELIMINARY, EXPLORATORY, MULTIVARIATE MODEL WHICH IS PREDICTIVE OF THE SERIOUSNESS OF AN OFFICIALLY RECORDED CRIMINAL CAREER. IT INVOLVES THE USE OF MULTIVARIATE DATA-REDUCTION TECHNIQUES TO PRODUCE A MODEL WHICH MAXIMIZES EXPLAINED VARIANCE. THE DEVELOPMENT OF THIS MODEL IS BASED ON THE CONJUNCTION OF TWO DATA SETS: (1) INFORMATION DERIVED FROM 1976 INTERVIEWS WITH A SAMPLE OF 333 MEMBERS OF THE 1942 COHORT AND WITH 556 MEMBERS OF THE 1949 COHORT; AND (2) THE OFFICIAL POLICE CONTACT RECORDS FOR COHORT SUBJECTS. EACH INTERVIEWEE'S RECORDED CRIMINAL CAREER HAS BEEN DIVIDED INTO THREE TIME SEGMENTS: (1) JUVENILE (AGES 6-17); (2) INTERMEDIATE (AGES 18-20); AND (3) ADULT (AGE 21 AND OLDER). THE STUDY OBJECTIVE WAS TO DEVELOP A SERIES OF REGRESSION MODELS PREDICTIVE OF JUVENILE, INTERMEDIATE, AND ADULT CAREER SERIOUSNESS SCORES IN EACH COHORT, AND TO PRODUCE A SINGLE LONGITUDINAL MODEL WHICH DESCRIBES THE JUVENILE THROUGH INTERMEDIATE THROUGH ADULT SEQUENCE AS A WHOLE. THE DEPENDENT VARIABLES ARE THE ADDITIVE SERIOUSNESS SCORES FOR EACH OF THE AGE PERIODS, DETERMINED BY ASSIGNING WEIGHTS TO EACH OFFENSE IN 6 MAJOR CATEGORIES OF OFFENSES. BACKGROUND AND PERSONAL HISTORY INDEPENDENT VARIABLES WERE DERIVED FROM THE INTERVIEWS. THE RESULTS SHOWED THAT WITHIN COHORTS THERE IS A DIFFERENCE IN THE PREDICTIVE MODELS OVER AGE PERIODS. ALSO, PREDICTIVE MODELS VARY ACROSS COHORTS FOR A GIVEN DEPENDENT VARIABLE. EACH OF THESE MODELS IS DISCUSSED. RESULTS OF THE DATA-REDUCTION PROCEDURE INDICATE THAT THE MOST PARSIMONIOUS MODEL OF THE SEQUENCE OF SERIOUSNESS SCORES THAT APPLIES FROM THE JUVENILE THROUGH THE ADULT PERIODS IN BOTH COHORTS IS ROOTED IN THE SINGLE VARIABLE, 'AGE AT FIRST POLICE CONTACT.' THE LOWER THE NUMBER OF YEARS OF FIRST POLICE CONTACT, THE HIGHER WILL BE SERIOUSNESS SCORES IN SUBSEQUENT AGE PERIODS. IT IS SUGGESTED THAT FUTURE RESEARCH SHOULD AIM AT DETERMINING THE CONDITIONS THAT ACCOUNT FOR VARIABILITY IN AGE AT FIRST POLICE CONTACT. DATA DERIVED FROM THE STUDY ARE INCLUDED IN THE APPENDIXES, AND A BIBLIOGRAPHY IS PROVIDED. (RCB)