How was the sample of young adults collected because I did not receive the survey?

The sample was collected statewide through a direct mail invitation and various social media sites, and includes a new sample/cohort at each year as well as annual follow-ups within cohorts. While it is not a random sample (and is instead a sample of convenience), data were weighted to match Washington Census data and improve generalizability. If you would like more information about the survey visit the Young Adult Health Survey site: https://blogs.uw.edu/uwwyahs/