Data Source: The National Survey on Drug Use and Health (NSDUH) is representative of persons aged 12 and over in the civilian noninstitutionalized population of the United States, in each state and the District of Columbia (D.C.). The survey covers residents of households (including those living in houses, townhouses, apartments, and condominiums), persons in noninstitutional group quarters (including those in shelters, boarding houses, college dormitories, migratory work camps, and halfway houses), and civilians living on military bases. Persons excluded from the survey include those experiencing homelessness who do not use shelters, active military personnel, and residents of institutional group quarters such as jails, nursing homes, mental institutions, and long-term care hospitals.
NSDUH uses an independent multistage area probability sample within each state and D.C. States are the first level of stratification, with each state further stratified into approximately equally populated state sampling regions (SSRs). Census tracts within each SSR were then selected and followed by census block groups. Finally, dwelling units (DUs) were selected within segments, and within each selected DU, up to two residents who were at least 12 years old were selected for interviews. Professional interviewers conduct the face-to-face surveys, and the data are used to support prevention and treatment programs, monitor substance use trends, estimate the need for treatment, and inform public health policy.
NSDUH provides multiple ways researchers can access survey data for use and provide analysis results in the Interactive NSDUH State Estimates or the substate estimates, available online: https://pdas.samhsa.gov/saes/state or https://pdas.samhsa.gov/saes/substate.
NSDUH also provides an online analysis tool using either the Public-Use Data Analysis System (PDAS) or the Restricted-Use Data Analysis System (RDAS) available from https://rdas.samhsa.gov/#/. PDAS allows users to explore the review study variables, run crosstab analyses, and download the results of analysis as a PNG image or as a data file in CSV format. The RDAS functions similarly to PDAS, but also allows exploring results over multiple survey years or year-pairs and includes surveys with location-based information. NSDUH results from RDAS may differ from the results produced by PDAS and from other published sources. This is due to differences in estimation methodology, rounding of results, and techniques used to protect the confidentiality of respondents. For PDAS, to protect the confidentiality of respondents, only a subsample of the original sample is used, and data that could be used to identify individuals have been excluded, encrypted, or collapsed. For RDAS, certain geographic identifiers (i.e., state) are available, but analyses are limited to a minimum of two survey years combined, and results are suppressed if they may present possible disclosure risks.
In addition, the NSDUH study state-level results view is based on a separate dataset that is computed using a Small Area Estimation (SAE) model, whereas the RDAS results are based on direct estimation. NSDUH strongly recommends review of the study’s codebook when interpreting results. To access the RDAS codebooks, select Data > NSDUH RDAS Codebooks from the SAMHDA main site's menu bar. To access the PDAS codebooks, select Data > Browse Series > NSDUH from the SAMHDA main site's menu bar and drill down to the appropriate study.