WLS Study Description
The WLS is a long-term study of a random sample of 10,317 men and women who graduated from Wisconsin high schools in 1957 and of their randomly selected brothers and sisters. Survey data were collected from the original respondents or their parents in 1957, 1964, 1975, and 1992, and from a selected sibling in 1977 and 1993. These data provide a full record of social background, youthful aspirations, schooling, military service, family formation, labor market experiences, and social participation of the original respondents. The survey data from earlier years have been supplemented by mental ability tests (of primary respondents and 2000 of their siblings), measures of school performance, and characteristics of communities of residence, schools and colleges, employers, and industries. The WLS records for primary respondents are also linked to those of three same-sex high school friends within the study population. In 1977 the study design was expanded with the collection of parallel interview data for a highly stratified sub-sample of 2000 siblings of the primary respondents. In the 1992-93 round of the WLS the sample was expanded to include a randomly selected sibling of every respondent with at least one brother or sister, and the content was extended to obtain detailed occupational histories and job characteristics; incomes, assets, and inter-household transfers; social and economic characteristics of parents, siblings, and children and descriptions of the respondents’ relationships with them; and extensive information about mental and physical health and well-being.
The WLS sample is broadly representative of white, non-Hispanic American men and women who have completed at least a high school education. Among Americans aged 50 to 54 in 1990 and 1991, approximately 66 percent were non-Hispanic white persons who completed at least 12 years of schooling. Some strata of American society are not well represented. The WLS sample is mainly of German, English, Irish, Scandinavian, Polish, or Czech ancestry. It is estimated that about 75 percent of Wisconsin youth graduated from high school in the late 1950s – everyone in the primary WLS sample graduated from high school; about seven percent of their siblings did not graduate from high school. Minorities are not well-represented: there are only a handful of African American, Hispanic, or Asian persons in the sample, though a project is currently under way to find all African Americans who graduated from Wisconsin high schools in 1957. About 19 percent of the WLS sample is of farm origin, and that is consistent with national estimates of persons of farm origin in cohorts born in the late 1930s. As in the later, large, longitudinal studies of school-based samples, age variation occurs in repeated observations rather than in cross-section. Also, siblings cover several adjoining cohorts: they were born primarily between 1930 and 1948. In 1964, 1975, and again in 1992, about two-thirds of the sample lived in Wisconsin, and about one-third lived elsewhere in the U.S. or abroad.
In 1992-93 a follow-up survey – of about 9,000 men and women who were first interviewed as seniors in Wisconsin high schools in 1957 and have subsequently been followed up in 1957, 1964, and 1975 – was completed. Most respondents were 53 or 54 years old when interviewed. Other members of the original sample who were not interviewed in 1975 (475 of 850 surviving non-respondents) have also been interviewed. In all, 8493 of the 9741 surviving members of the original sample have been interviewed. In 1993-94 randomly selected siblings of the high school graduates were interviewed. Some 2000 siblings were previously interviewed in 1977, and they and approximately 2800 additional siblings were interviewed in the 1993-94 round of the study. The surveys included a one-hour telephone interview followed by a 20-page, self-administered questionnaire. Brief, close-out interviews were carried out with a relative of respondents who have died, and, in cases in which the selected sibling has died, close-out data from the original respondent were obtained.