The National Survey on Drug Use and Health (NSDUH) is an annual survey that is the primary source of information on substance use and mental health measures in the U.S. civilian, noninstitutionalized population aged 12 or older. NSDUH reports provide estimates of these measures by various demographic or socioeconomic domains. This study evaluates how well NSDUH covers domains such as educational level, disability status, and low-income and uninsured adults by comparing NSDUH estimates with estimates from leading federal sources of information for these domains. This will allow analysts to make informed decisions about conducting domain-specific analyses. Coverage is defined as the ratio of a NSDUH domain estimate to the estimate from another source and was calculated at national and state levels. We discuss the selection of domains and the specific data sources, show how the coverage ratios were calculated, present ratios for a selected set of domains, and summarize how NSDUH estimates compare empirically with data from other sources.