NIS Database Documentation

The National (Nationwide) Inpatient Sample (NIS) is the largest publicly available all-payer inpatient care database in the United States, containing data on more than seven million hospital stays. Its large sample size is ideal for developing national and regional estimates and enables analyses of rare conditions, uncommon treatments, and special populations.

The following links provide detailed documentation for the NIS, from a high-level Overview to all the detailed specifications, restrictions, and resources necessary for researchers working and publishing with the NIS.
Description of NIS Database Restrictions on Use File Specifications and Load Programs Data Elements Additional Resources for Data Elements   ICD-10-CM/PCS Data Included in the NIS Starting With 2015 2012 NIS Redesign Known Data Issues NIS Supplemental Files HCUP Tools: Labels and Formats Obtaining HCUP Data

Internet Citation: HCUP NIS Database Documentation. Healthcare Cost and Utilization Project (HCUP). December 2020. Agency for Healthcare Research and Quality, Rockville, MD.
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Last modified 12/3/20