Nationwide Inpatient Sample The Nationwide Inpatient Sample (NIS) is one in a family of databases and software tools developed as part of the Healthcare Cost and Utilization Project (HCUP). A Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality, HCUP data inform decision making at the national, State, and community levels. This page provides an overview of the NIS. For more details, see Introduction to the NIS, 2006 (PDF file, 242 KB; HTML).
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The Nationwide Inpatient Sample (NIS) is a unique and powerful database of hospital inpatient stays. Researchers and policymakers use the NIS to identify, track, and analyze national trends in health care utilization, access, charges, quality, and outcomes. Key features of this database include the following:
The NIS excludes data elements that could directly or indirectly identify individuals. Purchase of the files is open to all users who sign a Data Use Agreement (PDF file, 55 KB; HTML). Users must agree to use the database for research and statistical purposes only and to make no attempts to identify individuals. Identities of institutions are available only in States where data sources already make that information public or agree to its release. For these institutions and for research purposes only, linkage is possible to data from the Annual Survey of the American Hospital Association's Annual Survey Database. Select for the Introduction to the NIS, 2006 (PDF file, 242 KB; HTML). |
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The NIS includes more than 100 clinical and nonclinical data elements for each hospital stay. These include:
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The Nationwide Inpatient Sample (NIS) for 2006 includes 1,045 hospitals from 38 States. Earlier releases of the NIS are also available, as displayed below:
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The NIS is a uniform, multi-State database that promotes comparative studies of health care services and will support health care policy research on a variety of topics including:
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The NIS has undergone some changes over time in 1) the sampling and weighting strategy, 2) the data elements that are available 3) the definitions of the data elements. For analyses that span multiple years, NIS Trends Supplemental files (NIS-Trends) are available to ease the burden of using multiple years of the NIS. These files contain revised trend weights and data elements that are consistently defined across data years. For more information, refer to the NIS Trends Supplemental Files http://www.hcup-us.ahrq.gov/db/nation/nis/nistrends.jsp. |
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NIS data can help answer a wide array of questions, such as:
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NIS data are used by a variety of non-profit and for-profit organizations, including:
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The NIS data set can be run on desktop computers with a CD-ROM reader, and comes in ASCII format. The data on the CD set require a statistical software package such as SAS or SPSS to use for analytic purposes. The data set includes weights for producing national and regional estimates. The documentation and tools, including programs to load the ASCII data into SAS, SPSS, or Stata, are available for downloading from this Website. |
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NIS releases for data years 1988-2006 are available from the HCUP Central Distributor. The 2006 NIS may be purchased for $200 in a set of two CD-ROMs with accompanying documentation. Contact the HCUP Central Distributor to complete your Data Use Agreement, answer questions about any year of the NIS, and to purchase your own copy. |
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For answers to commonly asked questions regarding HCUP databases and tools, please review the HCUP Index Page. If you cannot find an answer to your question, please contact HCUP User Support Staff. To reach HCUP User Support, please contact us by e-mail or phone:
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Additional information is available on the AHRQ Website. If you have comments, suggestions, and/or questions, please contact hcup@ahrq.gov. |
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Internet Citation: HCUP Databases.
Healthcare Cost and Utilization Project (HCUP). July 2008 Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/nisoverview.jsp. |
Last modified 7/11/08 |