Agency for Healthcare Research and Quality (AHRQ)
Years Available
1988 to present
The Healthcare Cost and Utilization Project (HCUP) is a family of health care databases and related software tools developed through a federal-state-industry partnership to build a multistate health data system for health care research and decision making. The National (Nationwide) Inpatient Sample (NIS), a component of HCUP, is the largest all-payer inpatient care database that is publicly available in the U.S. Beginning with 2012 data year, the NIS was redesigned. It approximates a 20-percent stratified sample of all discharges from US community hospitals, excluding rehabilitation and long-term acute care hospitals. Weights are provided to trend across the two different designs.
Population Covered
The 2016 HCUP NIS includes all discharge data from 4,573 hospitals. This 2016 NIS sampling frame is comprised of 46 states and the District of Columbia, covering more than 97% of the US population and includes almost 96% of dischargers in the US community hospitals. The number of states included in the NIS varies by year and has grown from 8 in the first year to 47 (including the District of Columbia) at present.