National Hospital Discharge Survey (NHDS) Restricted Variables
The majority of NHDS variables are publicly available and researchers are highly encouraged to conduct preliminary analyses using the public use files. However, confidential variables, such as the survey design variables, are restricted and must be accessed through the RDC. Researchers interested in using restricted NHDS variables must seek RDC approval. As part of the approval process, researchers are required to submit a proposal to the RDC that includes a data dictionary describing the variables needed for analysis. Please note that restricted data files cannot be merged with public data files, but they do contain all the variables on public use files. Because some variables may have slightly different coding in the public and restricted datasets, it is important to refer to the codebook provided when creating data dictionaries for your proposal.
NHDS Restricted Variable Codebook 1988-present