Professional interviewers from the Census Bureau experienced with health surveys administered the in-person interviews, after ten days of centralized training supervised by NIAAA. Regional supervisors re-contacted a random 10% of all respondents to verify interviews. Further, 2,657 randomly selected respondents were re-contacted and re-asked 1 to 3 sections of the interview, providing NESARC reliability data. 30 In the few cases with uncertain accuracy, data were discarded and a supervisor repeated the interview.
