Within-Dwelling Unit Sampling

The 1997 NHSDA used basically the same within-dwelling unit sample selection approach as the 1996 NHSDA. Following the third-stage sampling, interviewers screened each sampled dwelling unit. Based on the screening, the dwelling was classified according to the race/ethnicity of the head of the dwelling. The interviewers also determined the age domains represented by individuals residing in the dwelling in terms of presence or absence of individuals aged 12 to 17, 18 to 25, 26 to 34, 35 to 49, and 50 or older. Interviewers were provided a mechanism for selecting none, one, or two age domains and, subsequently, one sample person from each selected domain. The age domain selection probabilities were based on the desired sample sizes for each age group by racial/ethnic domain. If a dwelling unit contained two or more individuals in the same age domain, the probability of selecting a particular individual was based on the number of individuals in the age domain. In some instances, two individuals, usually one 12 to 17 year old and one adult, were selected from the same dwelling unit.