The respondent universe for the 2013 National Survey on Drug Use and Health (NSDUH) was the civilian, noninstitutionalized population aged 12 years or older residing within the 50 States and the District of Columbia. Consistent with the NSDUH designs since 1991, the 2013 NSDUH universe included residents of noninstitutional group quarters (e.g., shelters, rooming houses, dormitories, and group homes), residents of Alaska and Hawaii, and civilians residing on military bases. Coverage before the 1991 survey was limited to residents of the coterminous 48 States, and it excluded residents of group quarters and all persons (including civilians) living on military bases. Persons excluded from the 2013 universe included those with no fixed household address (e.g., homeless and/or transient persons not in shelters), the active military, and residents of institutional group quarters, such as jails and hospitals.