The "High School Senior Cohort Study for 1965 and 1973" is a two-part machine-readable data file (MRDF) containing background information about the social and political climate of the peer groups and the entire senior classes of the high school students interviewed for the "Student-Parent Socialization Study, 1965" (ICPSR-7286). The schools in each year of the study were defined from the original 97 schools in the "Student-Parent Socialization Study." Seventy-seven (77) schools cooperated in 1965; eighty-five (85) schools cooperated in 1973. The 1973 data in the second of the two files were gathered largely to provide a trend line. Within cooperating schools, all members of the senior class were given paper-pencil questionnaires and were potential respondents. Respondents in 1965 amounted to 20,674 (85% response rate); respondents in 1973 amounted to 16,929 (74% response rate). The weighted data provide a sample that can be considered representative of all high school seniors in the United States during the mid-1960s. In both years of the study, several key political measures (e.g., trust, tolerance, cosmopolitanism, partisanship, and personal measures) were used that paralleled those in the 1965 student-parent interviews. The 1965 data included more political, ethnic, and racial variables. Information about the high schools represented in each year of the study was collected from school officials through a separate school characteristics form. School characteristics data are located at the end of each dataset. Among the 115 and 141 variables captured by each file, respectively, are: attitude toward politics; concept of good citizenship; faith in government; interest in politics; attitude toward federal government; interest in public affairs; school activities; academic courses taken; personal and family background; academic plans; occupational plans. Duncan Occupation Codes are used to identify occupations. Study conclusions are reported in two publications: (1) "An Aggregate Analysis of Home and School Effects on Political Socialization," by M. Kent Jennings (Social Science Quarterly, September 1974, p.394-410); (2) "The Political Texture of Peer Groups," by Suzanne Sebert, M. Kent Jennings, and Richard G. Niemi (in "The Political Character of Adolescence," by Jennings and Niemi, Princeton University Press, 1974, Chapter 9). POPULATION: High school seniors, 1965 and 1973; high schools, 1965 and 1973. TYPE OF SURVEY: National Survey; Sample Survey. SAMPLE: High school seniors (1965--24,322), (1973--22,877); high schools (97). RESPONSE RATE: High school seniors (1965--20,674=85%), (1975--16,929=74%); high schools (1965--77=79.3%), (1973--85=87.6%). FREQUENCY: Periodic. YEAR OF FIRST DATA: 1965. YEAR OF LATEST DATA: 1973. (CDM/WTB)