NESARC participants were non-institutionalized civilians aged 18 and over drawn from all fifty states and the District of Columbia. Young adults, aged 18 to 24, were over-sampled at a 2.25:1 ratio, and African American and Hispanic individuals were over-sampled to each constitute approximately 20 percent of the total sample. The sample was weighted to account for the selection of one person from each household and for over-sampling and other sampling methods, and to adjust for non-response at the household level. Weighting allowed adjustment of the data during analyses to represent the U.S. population on demographic variables including age, sex, race, ethnicity, and region of residence based on the 2000 Decennial Census results.
