Respondents were drawn from a nationally representative random-digit-dial sample of non-institutionalized, English-speaking adults, aged 25-74, selected from working telephone banks in the coterminous United States. It is comprised of individuals from four subsamples: (1) a national RDD (random digit dialing) sample (n=3,487); (2) oversamples from five metropolitan areas in the U.S. (n=757); (3) siblings of individuals from the RDD sample (n=950); and (4) a national RDD sample of twin pairs (n=1,914).
Selection Criteria
Minimum age
25
Maximum age
74
Countries
United States of America
Sources of Recruitment
General Population
Random digit dialing
Specific Population
Other specific population : In addition to the general population: siblings of individuals from the RDD sample; a national RDD sample of twin pairs