What kinds of NHANES documents are available and how is it best to use them?
There are three types of data documentation for each data file that you need to consult, and each provides valuable information to facilitate your gathering of background information on your variables. The three documentation types are: • codebook, • data file documentation, and • frequency tables. Before analyzing the data, you will need to know how the variable is coded, data editing, processing, and collection information, and the frequency (or sample size) of the variable. The codebook lists all the variables in the data file. Use it to determine what the values associated with a variable mean. Use the data file documentation to determine if the collection or measurement is appropriate for your analysis. The frequency files for each data file contain the frequency count for each item in the data file and can be used to verify the sample size for a particular data item.
