National Survey on Drug Use and Health

The coordinated sample design is state-based, with an independent, multistage area probability sample within each state and the District of Columbia. States were the first level of stratification. Each state was further stratified into approximately equally populated state sampling regions (SSRs). Creation of the multistage area probability sample then involved selecting census tracts within each SSR (Stage 1), census block groups within census tracts (Stage 2), and area segments (i.e., a collection of census blocks) within census block groups (Stage 3). Finally, the dwelling units (DUs) were selected within segments (Stage 4), and (within each selected DU) up to two residents who were at least 12 years old were selected for the interview (Stage 5).

Though earlier years had mix of computer assisted interviewing (CAI) and personal interviews, in Quarter 4 of 2020 web-based interviewing became the primary means of gathering data. In addition, data collection during Quarter 2 and Quarter 3 of 2020 were suspended due to the COVID-19 pandemic. Data collection in 2021 became a hybrid of web-based and in-person surveys, whereas in years prior to 2020 it was wholly in-person. SAMHSA does not recommend comparing 2020 with any other years. Data from 2021 can be compared with subsequent years but not prior years. Please see this FAQ at https://www.samhsa.gov/data/release/2021-national-survey-drug-use-and-health-nsduh-releases for more information regarding compatibility issues with 2020 and 2021 data.