DELINQUENCY RESEARCHERS HAVE LONG STRUGGLED WITH THE PROBLEM OF SECURING RELIABLE DATA TO DETERMINE THE INCIDENCE AND DISTRIBUTION OF DELINQUENT BEHAVIOR IN THE ADOLESCENT POPULATION. CONCEPTUAL AND MEASUREMENT PROBLEMS HAVE CONFOUNDED THIS STRUGGLE ALONG WITH THE CONTINUING CONTROVERSY OVER THE USE OF OFFICIAL VERSUS SELF-REPORT INDEXES AS THE APPROPRIATE BASIS FOR ESTIMATION. THE PRESENT STUDY WAS DESIGNED TO OVERCOME SOME OF THE TRADITIONAL PROBLEMS INVOLVING SELF-REPORT MEASURES AND PRIOR ATTEMPTS TO ESTIMATE ADOLESCENT INVOLVEMENT IN ILLEGAL ACTS. THIS NATIONAL SURVEY OF YOUTH INVOLVES A THREE-WAVE PANEL DESIGN WITH A NATIONAL PROBABILITY SAMPLE OF APPROXIMATELY 1,725 ADOLESCENTS AGED 11 THROUGH 17 IN 1976. THE TOTAL YOUTH SAMPLE WAS SELECTED AND INTERVIEWED INITIALLY BETWEEN JANUARY AND MARCH 1977 CONCERNING THEIR INVOLVEMENT IN DELINQUENT BEHAVIOR DURING 1976. A SECOND SURVEY, IN 1978, OBTAINED ESTIMATES FOR 1977. A THIRD SURVEY WILL COLLECT DATA FROM 1978. THE CENTRAL CONCERNS WHICH WERE ADDRESSED IN THE DEVELOPMENT OF THE SELF-REPORT DELINQUENCY MEASURE ARE DISCUSSED AT LENGTH. SINCE THE SELF-REPORT MEASURES WERE DESIGNED SPECIFICALLY TO DEAL WITH SEVERAL OF THE MAJOR CRITICISMS OF EXISTING SELF-REPORT MEASURES, THE MAJOR ISSUES ARE PRESENTED WITH A BRIEF DESCRIPTION OF THE ADAPTATIONS MADE IN THE PRESENT MEASURE TO ACCOMMODATE EACH ISSUE. THE DATA PRESENTED OFFER CURRENT RELIABLE INFORMATION ON THE INCIDENCE OF DELINQUENT BEHAVIOR IN THE UNITED STATES. FUTURE PUBLICATIONS UTILIZING THE SAME DATA BASE WILL ADDRESS THE ISSUES OF EPIDEMIOLOGY OF DELINQUENT BEHAVIOR AND THE TESTING OF THEORETICAL PROPOSITIONS. FOOTNOTES, DATA TABLES, AND A SAMPLE SELF-REPORT QUESTIONNAIRE ARE PROVIDED. FOR RELATED INFORMATION, SEE NCJ 68063.