Nationwide/National Inpatient Sample (NIS)

Topic/focus: Healthcare Facilities and Services, Cost and Utilization
Year(s): 1988 - Present
Source: Agency for Healthcare Research and Quality
Study and sample characteristics: Administrative hospital records
Universe: Discharges from non-Federal, short-stay hospitals
Variables: ~120
Access: Contact EDRC Coordinator
Cost: Contact EDRC Coordinator
Key web links: Nationwide Inpatient Sample (NIS)
Primary Institutional Contact: EDRC Coordinator (

Summary: The NIS is one database in the ARHQ's Healthcare Cost and Utilization Project (HCUP) family of databases. The NIS database contains hospital inpatient stay information taken from 100% of discharges from sampled hospitals in selected states. This design is intended to approximate a 20% sample of U.S. hospitals. Between 700 and 1,000 hospitals per year are included, drawn from between 8 and 38 states. The most recent release of the NIS includes data from Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, Nevada, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Vermont, Washington, West Virginia, and Wisconsin. Data items in the NIS include demographics, diagnoses, procedures, admission and discharge dates and status, and payer information. The NIS can be linked to hospital-level data from the American Hospital Association's Annual Survey of Hospitals and county-level data from the Bureau of Health Professions' Area Resource File.

A significant change in the sampling method of the NIS occurred with the 2012 release. Please refer to the documentation for information on this change and how it might affect your analyses.