these differences are quite small and often do not significantly affect the original distribution of these variables as established at the first wave of the NYS, which has been shown to be representative of individuals born in the continental U.S. in 1959–1965. One of the few significant and the largest of these is a change from 53.2% to 49.2% male (46.8% to 50.8% female) from the 1st to 10th survey. There has been no significant disproportionate loss over the years by initial alcohol use, marijuana use, or other illicit drug use or by general delinquency or more serious Uniform Crime Rates (UCR) offending. The distributions of these variables are not significantly different between respondents who completed interviews in a given year and those who did not. In addition, the distributions of sex, age, race/ethnicity, and social class of waves 7–10 are usually not significantly different from those observed in Wave 1 (1976) or Wave 6 (1983). Thus, overall, the NYS sample appears to remain reasonably representative of the U.S. population born in 1959–1965. The sample consisted of 227 families with sibships ranging from 2 to 5 offspring per family (592 individuals) and 479 individuals without siblings in the sample. 48.1%
