The Wisconsin Longitudinal Study (WLS) is a long-term study of a random sample of 10,317 men and women who graduated from Wisconsin high schools in 1957. The WLS provides an opportunity to study the life course, intergenerational transfers and relationships, family functioning, physical and mental health and well-being, and morbidity and mortality from late adolescence through 2008. WLS data also cover social background, youthful aspirations, schooling, military service, labor market experiences, family characteristics and events, social participation, psychological characteristics, and retirement.

Data Collection

WLS is based on a 1/3 sample of all 1957 Wisconsin high school graduates (N=10,317) and a sibling of these graduates. Survey data were collected from the original respondents or their parents in 1957, 1964, 1975, 1992, and 2004; from a selected sibling in 1977, 1994, and 2005; from the spouse of the original respondent in 2004; from the spouse of the selected sibling in 2006; and from widow(er)s of the graduates and siblings in 2006.  The graduate respondents were empaneled with an in-person questionnaire in 1957, which has been followed with data collection in 1964 (a mail survey of parents), 1975 (telephone survey), 1993 (telephone and mail surveys), 2004 (telephone and mail surveys, as well as a spouse telephone survey), and 2011 (in-person and mail). The paired sibling was randomly selected from a roster of all siblings except in the case of twins where the twin was selected.  In 1977, 2000 siblings were first empaneled and the full sibling sample was implemented in 1994.  A sibling survey has been fielded in each round, and siblings are being surveyed concurrent to graduates in the ongoing round of data collection. In-Person interviews of the class members and one of their siblings began in March of 2010 and concluded in December of 2012. Beginning of the 2010–2011 round of data collection, interview protocols were – for the first time – relaxed to allow proxies to complete the interview on their behalf.


The WLS includes a variety of direct biometric measures, including height, weight, waist and hip circumference, grip strength, lung function, gait speed, and mobility.  In 2006/2007 WLS collected saliva samples from respondents using Oragene kits and a mail-back protocol.  WLS obtained samples from 4527 graduates and 2517 siblings.  This represented a cooperation rate of 56% among all survivors for both graduates and siblings. Samples have been assayed for 95 SNPs using KBioscience. Our consent form permits flexible use of the DNA samples. The large stores of DNA that we have collected enable us to undertake multiple assays over a period of years. Samples are currently being collected from participants who did not respond to the mail-back protocol and for the few samples that were unusable.  Based on cooperation rate of other face-to-face elicitations of saliva samples in other studies, a 65-70% response rate is expected among the survey participants, thus yielding 4200 new samples. The new samples will strengthen sibling pair analysis. The number of complete sibling pairs with DNA samples is projected to increase from the 1146 pairs (2292 respondents) to ~2480 (4920 respondents). In 2011, a random sample of 500 participants were selected to participate in the Microbiome Pilot (MiBi) Sample, out of which 329 participants completed (68.7% response rate). The gut microbiome was a newly added biomarker as its plasticity may help researchers to understand how environments shape the composition of the gut microbiome, which is also linked to health and mortality.

DNA Genotyping Data