The 2004 National Nursing Home Survey (NNHS), conducted between August and December of 2004, was reintroduced into the field after a five-year break, during which time the survey was redesigned and expanded to collect many new data items. The 2004 NNHS included a supplemental survey of nursing assistants employed by nursing homes, the National Nursing Assistant Survey (NNAS), which was sponsored by the Office of the Assistant Secretary for Planning and Evaluation (APSE). Nursing assistants were considered eligible to participate in the survey if they 1) provided assistance with activities of daily living (ADLs); 2) were paid to provide those services; 3) were certified (or in the process of certification) to provide Medicare/Medicaid reimbursable services; 4) worked at least 16 hours per week; and 5) were employees of the nursing home and not contract employees. A sample of up to eight nursing assistants was selected from about half of the nursing home sample at the time of the facility interview. The NNAS was administered after the nursing home visit, using a computer-assisted telephone interview (CATI) system.