An NHANES III dataset for analysis will typically include data from at least 2 data files. You will keep and merge data to include variables from different data files.
NHANES III data files are released by their collection method, and as supplemental data files. Many of these are very large data files with many variables. Most analysts will only need a few selected variables. You will likely wish to keep only those variables when you create your analytic dataset. This process is called keeping.
The basic data files were organized by their collection method, which can fall under one of four components: Examination, Laboratory, Adult or Youth Questionnaire, or Foods. To allow for timelier releases, supplemental data files (component updates and specialized sub-sections of these components) were released at later dates as they were completed. Joining the components of the data files is called merging.
National Center for Health
Statistics
3311 Toledo Road
Hyattsville, MD 20782
Phone: 1-866-441-NCHS (6247)
For data inquiries, use
nchsquery@cdc.gov
Problems or comments about the Tutorial?
Email the Tutorial Team: NHANESWebTutorial@cdc.gov
Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333, U.S.A
Tel: (404) 639-3311 / Public Inquiries: (404) 639-3534 / (800) 311-3435