This page provides answers to commonly asked questions about obtaining and using the Healthcare Cost and Utilization Project (HCUP) databases, software tools, supplemental files, and other products. It also covers certain questions about data use restrictions and publishing with the data. Links throughout these FAQs direct you to the complete documentation resources for working with HCUP data. If you still have questions, please use the following contact information as a guide to identify the correct support resource.

For questions about using the HCUP databases, software tools, supplemental files, and other products, or about data use restrictions and publishing with the data, contact HCUP User Support at HCUP@ahrq.gov. Additional information regarding HCUP User Support is located in the About HCUP User Support section below.

For questions concerning HCUP database purchases, current HCUP database orders and invoices, downloading nationwide HCUP databases, unzipping State or nationwide HCUP database products, the submission of required HCUP Data Use Agreements (DUAs), training certificate codes, or data re-use requests, please review the Purchasing FAQs, or contact the HCUP Central Distributor at HCUPDistributor@ahrq.gov.

For questions about using the AHRQ Quality Indicators™ (QIs), visit the AHRQ Quality Indicators page or contact QIsupport@ahrq.hhs.gov.

• What is HCUP?
  
  The Healthcare Cost and Utilization Project (called "H-CUP") is a family of healthcare databases, software tools, and products developed through a Federal-State-Industry partnership and sponsored by the Agency for Healthcare Research and Quality (AHRQ). HCUP databases bring together the data collection efforts of State data organizations, hospital associations, private data organizations, and the Federal government to create a national information resource of patient discharge-level healthcare data.
  
  HCUP includes the largest collection of longitudinal hospital care data in the United States, with all-payer, encounter-level information beginning in 1988. HCUP is derived from administrative data originally collected for billing purposes. These databases enable research on a broad range of health policy issues, including cost and quality of health services, medical practice patterns, access to healthcare programs, and outcomes of treatments at the national, State, and local levels.
  
  HCUP offers free software tools that facilitate use of the data, including HCUPnet, an online query system that provides immediate access to statistics on hospital inpatient, emergency department, and ambulatory surgery use, cost, and readmissions.
  
  HCUP Fast Stats provides easy access to the latest HCUP-based statistics for healthcare information topics using visual statistical displays in stand-alone graphs, trend figures, or simple tables to convey complex information at a glance.
  
  HCUP offers online reports, including HCUP Statistical Briefs which present simple, descriptive statistics on a variety of specific topics.
  
  For additional information, please visit the Overview of HCUP page and take the Online HCUP Overview Course.



• What types of healthcare settings are captured in HCUP data?
  
  The HCUP databases are built from hospital administrative data (i.e., hospital billing records). The databases cover hospital inpatient care, outpatient emergency department care, and ambulatory surgery from hospital-owned facilities. Some State Ambulatory Surgery and Services Databases (SASD) include ambulatory surgery data from facilities not owned by a hospital. HCUP does not include services provided in physician offices, and does not contain complete or reliable pharmacy, laboratory, pathology, or radiology information.



• Under the Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule, how are the HCUP databases defined?
  
  The HCUP databases are consistent with the definition of limited data sets under the HIPAA Privacy Rule and contain no direct patient identifiers. HCUP Data Use Agreement (DUA) training and a signed DUA are required to purchase and/or use the HCUP databases.



• What is HCUP's unit of analysis?
  
  The unit of analysis in the HCUP databases is the discharge record, not individual patients.



• How can I keep informed about HCUP activities and product releases?
  
  Sign up for the HCUP Mailing List to receive emailed information about database releases, tools, and other HCUP product news. You also can check the HCUP-US News and Events page for updates.

• What are HCUP's nationwide databases?
  
  HCUP's nationwide databases provide estimates for hospital stays or emergency outpatient encounters across the United States. Consisting of the NIS, KID, NASS, NRD, and NEDS, the nationwide databases are built from the HCUP State Databases. The databases contain information on all discharges or encounters, regardless of expected payers. They can be used to create national estimates of healthcare utilization, access, charges, quality, and outcomes. The HCUP nationwide databases are available for purchase through the HCUP Central Distributor. Statistics from the databases are available on HCUPnet.



• Do I need to weight my nationwide database data?
  
  Yes, HCUP's nationwide databases need to be weighted to produce national estimates. HCUP's free online tutorial called Producing National HCUP Estimates provides instruction on the process.



• When are the nationwide databases generally released, and what years of data are available?
  
  The NIS, NASS, NEDS and NRD, are released annually, approximately 18 to 22 months following the end of a calendar year. Data years begin with 1988 for the NIS, 2016 for the NASS, 2006 for the NEDS, and 2010 for the NRD.
  
  The KID is released every 3 years, approximately 18 months following the end of a calendar year. Data years begin with 1997 and run through 2012. The KID resumed release in 2016.
  
  Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog. Database releases also are noted on a monthly basis in the HCUP Database and Product Releases Calendar.

• What is the National Inpatient Sample?
  
  The National Inpatient Sample (NIS) is the largest publicly available all-payer inpatient care database in the United States, yielding national estimates of hospital inpatient stays. In 2012, the National Inpatient Sample replaced the original NIS (the Nationwide Inpatient Sample), which consisted of discharge data from a sample of hospitals. Sampled from the State Inpatient Databases (SID), the National Inpatient Sample (NIS) contains a systematic sample of discharges from all hospitals reporting to HCUP. It contains charge information on all patients, regardless of expected payer.
  
  The most recent version of the NIS (data year 2018) contains a sample of discharges from all HCUP-reporting hospitals, which totaled more than 4,500 in 2018.
  
  Additional information on the NIS, including a description of data elements and summary statistics, can be found on the NIS Database Documentation page. The database can be purchased through the HCUP Central Distributor, and statistics from the NIS are available on HCUPnet.



• What is the Nationwide Inpatient Sample?
  
  The Nationwide Inpatient Sample (NIS) contains discharge data from a national sample of community hospitals for data years prior to 2012. Sampled from the SID, the NIS includes all discharge data from more than 1,000 hospitals each year, approximating a 20 percent stratified sample of U.S. community hospitals through the 2011 data year. The NIS contains charge information on all patients, regardless of expected payer.
  
  Starting with database year 2012, the Nationwide Inpatient Sample was replaced with the National Inpatient Sample. The National Inpatient Sample uses a redesigned sampling method and contains data on more than seven million hospital stays each year that can be weighted to make national estimates.



• What are the differences between the Nationwide Inpatient Sample and the National Inpatient Sample?
  
  The National Inpatient Sample replaces the Nationwide Inpatient Sample for database year 2012 onward. The National Inpatient Sample implements an improved sample design for more accurate representation of national discharge data. The previous NIS contained all discharge records from a sample of hospitals participating in HCUP. The revised database contains a sample of discharge records from all hospitals participating in HCUP.
  
  The database was redesigned in 2012 to improve national estimates. The redesign reflects three types of changes:
  
  
  • Revisions to the sample design, which now creates a sample of discharge records from all HCUP-participating hospitals rather than all discharge records from a sample of hospitals
  • Revisions to the definition of the discharge universe
  • Revisions to enhance confidentiality by eliminating State identifiers and data elements that are not uniformly available across States.
  
  The new sample strategy is expected to result in more precise estimates than the previous NIS design by reducing sampling error: for many estimates, confidence intervals under the new design are about half the length of confidence intervals under the previous design. For a detailed description of the NIS redesign, please refer to the NIS Redesign Report (PDF file, 2.1 MB).



• Can I perform State-level analyses with the NIS?
  
  The sampling methodology used to create the NIS does not include State as a stratifier; therefore analysts cannot use the database to generate State-level estimates. Although the NIS includes weights to allow researchers to generate national estimates from the raw counts, no weights are included for the calculation of State-level estimates.
  
  For information on State-specific inpatient stays, we recommend that you work with the HCUP SID.
  
  
• Can I perform multi-year or trend analysis using the NIS?
  
  Because the NIS spans more than 20 years of data, it is a good tool for longitudinal analysis. However, the NIS has undergone various changes over time, including changes to the sampling and weighting strategies used. The NIS was significantly redesigned for database year 2012. For trend analysis spanning 2012 and earlier years, revised discharge weights should be used to make estimates comparable to the new 2012 NIS design.
  
  To perform multi-year or trends analysis using the NIS, AHRQ developed discharge trend weights for the 1993-2011 NIS, specifically the NIS Trend Weight Files. These weights were calculated in the same way that weights were calculated for the redesigned 2012 NIS and are designed to be used instead of the original NIS discharge weights for trend analyses.
  
  For trend analyses spanning 2012 and earlier NIS data, trend weights should be used prior to 2012 data to make estimates comparable to the new 2012 NIS design. Use the trend weight (TRENDWT) in place of the original discharge weight (DISCWT) to create national estimates for trend analysis. For 2012 or later data, no trend weight is necessary and the discharge weight supplied on the NIS files can be used. The trend weights are available for download as ASCII files along with SAS®, Stata®, and SPSS® load programs from the HCUP-US website.
  
  These revised 1993-2011 trend weights replace the earlier NIS trend weights that were developed for the 1988-1997 NIS following the 1998 NIS redesign. The report Using the HCUP National Inpatient Sample to Estimate Trends (PDF file, 1.3 MB) is available as a Methods Series report and includes recommendations for trend analysis.



• Are the NIS data weighted?
  
  NIS data sets purchased through the HCUP Central Distributor include discharge weights, which the user must apply to produce national estimates. When combining NIS data prior to and after its redesign in 2012, NIS trend weights should be applied. It is not necessary to use the trend weights (or discharge weights) with the NIS if you are not interested in producing national estimates.
  
  To learn how to properly weight data, consult HCUP's free online tutorial called Producing National HCUP Estimates, which describes the process of applying the weighting to your data.
  
  Please note that if you are using HCUPnet (HCUP's free, online query system), the weighting already has been applied—the statistics produced are national estimates.



• How often is the NIS released, and what years are available?
  
  The NIS is released annually, approximately 18 months after the end of a calendar year. Data years begin with 1988. Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog.



• What are some best practices when working with the NIS?
  
  To ensure researchers' appropriate use of the NIS, AHRQ released a Checklist for Working With the NIS. The checklist, available for download here on the HCUP-US website, helps researchers, manuscript peer reviewers, and journal editors understand the NIS database design, its strengths and limitations, and how it has changed over time. The checklist provides a step-by-step guide detailing key elements to consider when evaluating NIS studies.
  
  Additionally, the checklist refers to informational resources covering four key topics:
  
  
  • NIS data use and acknowledgements
  • Research design
  • Data analysis
  • Transition from ICD-9-CM to ICD-10-CM/PCS.
  
  
  The checklist was derived from the JAMA article titled Adherence to Methodological Standards in Research Using the National Inpatient Sample by Khera and colleagues.
  
  
• How much does the NIS cost?
  
  Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog. Cost varies by year of data. Student pricing is available.
  
  Additionally, statistics and data tables from the NIS are available on HCUPnet, HCUP's free, online query system.

• What is the Kids' Inpatient Database (KID)?
  
  The KID is the largest publicly available all-payer pediatric inpatient care database in the United States, yielding national estimates of hospital inpatient stays for patients younger than 21 years of age. Unweighted, it contains data from approximately three million pediatric discharges each year that can be weighted to make national estimates for pediatric care. Weighted, it estimates approximately six million hospital stays for children. The KID is built from a sample of pediatric discharges from the SID.
  
  The KID has been produced every 3 years (1997, 2000, 2003, 2006, 2009, 2012). Hospital discharge data for 2015 contains a mix of ICD-9 and ICD-10 data—the first three quarters of 2015 contain ICD-9-CM data, and the last quarter contains ICD-10-CM/PCS data. Because of the complexities of analyzing a mixed data year, the KID was not released for 2015 but instead was released for 2016. The 2016 KID consists of ICD-10-CM/PCS data only. The 2016 KID includes discharges from 4,200 hospitals in 46 States plus the District of Columbia.
  
  Although the KID is released every 3 years, the data include discharges for the single calendar year (January to December). The KID's large sample size enables analyses of common as well as rare conditions, such as congenital anomalies, and uncommon treatments, such as organ transplantation. The KID includes charge information on all patients, regardless of expected payer.
  
  Additional information on the KID, including a description of data elements and summary statistics, can be found on the KID Database Documentation page. The database can be purchased through the HCUP Central Distributor, and statistics from the KID are available on HCUPnet.



• How is the KID different from the NIS?
  
  The KID is based on a stratified, random sample of pediatric discharges (patients younger than 21 years of age) from the SID. Ten percent of normal newborns and 80 percent of other pediatric discharges (age 20 years or younger at admission) from 4,200 U.S. community hospitals (defined as short-term, non-Federal, general and specialty hospitals, excluding hospital units of other institutions), excluding rehabilitation hospitals. A large sample size enables analyses of rare conditions (e.g., congenital anomalies) as well as uncommon treatments (e.g., cardiac surgery).
  
  The NIS does not oversample complicated newborns and other (nonnewborn) pediatric discharges. The 2012 NIS is a sample of discharges from all hospitals participating in HCUP. Starting with 2012 data, the NIS was redesigned to improve national estimates; the previous NIS contained all discharge records from a sample of hospitals participating in HCUP.



• Are the KID data weighted?
  
  KID data purchased through the HCUP Central Distributor include discharge weights, which must be applied by the user to produce national estimates. To learn how to properly weight data, consult HCUP's free online tutorial Producing National HCUP Estimates, which describes the process of weighting data.
  
  Please note that if you are using HCUPnet (our free, online query system), the weighting already has been applied — the statistics produced are national estimates.



• How often is the KID released, and what years are available?
  
  Unlike HCUP's other databases, which are released annually, the KID was released every 3 years beginning with 1997 data through 2012. The KID resumed release in 2016 following the transition from ICD-9-CM to ICD-10-CM/PCS code sets for reporting clinical diagnoses and inpatient procedures on October 1, 2015. Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog.



• How much does the KID cost?
  
  Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog. Cost varies by year of data. Student pricing is available.
  
  Additionally, statistics and data tables from the KID are available on HCUPnet, HCUP's free, online query system.

• What is the Nationwide Ambulatory Surgery Sample (NASS)?
  
  The NASS is the largest all-payer ambulatory surgery database that has been constructed in the United States, yielding national estimates of major ambulatory surgery encounters performed in hospital-owned facilities. The NASS contains clinical and resource-use information that is included in a typical hospital-owned facility record, including patient characteristics, clinical diagnostic and surgical procedure codes, disposition of patients, total charges, expected source of payment, and facility characteristics.
  
  Major ambulatory surgeries are identified through Healthcare Common Procedure Coding System (HCPCS) Level I codes, also known as Current Procedural Terminology (CPT®) codes. Major ambulatory surgeries are selected invasive therapeutic surgical procedures that typically require the use of an operating room and regional anesthesia, general anesthesia, or sedation.
  
  The 2018 NASS includes data from 32 HCUP Partners. These States are geographically dispersed and account for 82 percent of the total U.S. resident population, an estimated 63 percent sample of the universe of hospital-owned facilities, and an estimated 72 percent sample of the universe of ambulatory surgery encounters.
  
  Additional information on the NASS, including a description of data elements and summary statistics, can be found on the NASS Database Documentation page. The database can be purchased through the HCUP Central Distributor.



• What facilities are included in the NASS?
  
  The NASS is restricted to hospital-owned facilities in the HCUP State Ambulatory Surgery and Services Databases (SASD) that perform major ambulatory surgeries. In addition to restricting attention to hospital-owned facilities, facility selection criteria for the NASS are (1) community nonrehabilitation hospital type and (2) a service type of either general acute care or children's. This means that specialty hospitals (e.g., heart, orthopedic, women's) are not included in the current NASS design. Additional restrictions imposed for the NASS sampling frame are that the hospital (1) have no gross irregularities in quarterly reporting volume, (2) submit data to the SASD in all four quarters of the data year, and (3) not have an unusually low volume of encounters containing an in-scope major ambulatory surgery.
  
  The HCUP SASD contain a number of hospital-owned facilities performing major ambulatory surgeries that are not inpatient hospitals. In the NASS, these facilities are assigned the identifier of the hospital owner. Stratification, sampling, weighting, and reporting are performed using the hospital owner identifier and hospital characteristics.
  
  Additional information about the NASS sampling frame can be found in the Introduction the NASS document on the NASS Database Documentation page.



• What procedures are included in the NASS?
  
  The NASS is limited to encounters with at least one in-scope major ambulatory surgery on the record, performed at hospital-owned facilities. In-scope major ambulatory surgeries are defined as selected invasive, therapeutic surgical CPT-coded procedures that typically require the use of an operating room and regional anesthesia, general anesthesia, or sedation. These surgeries are flagged as narrow in the HCUP Surgery Flag Software. They also belong to a subset of Clinical Classifications Software (CCS) for Services and Procedures procedure groups with a relatively high major ambulatory surgery volume, a substantial share of major ambulatory surgeries performed in hospital-owned facilities, and evidence of reliable reporting from SASD hospitals. For a detailed list of in-scope CCS procedure groups, see the Introduction to the NASS document on the NASS Database Documentation page.
  
  Note that although encounters are limited to those with at least one in-scope major ambulatory surgery on the record, the NASS Supplemental File provides information on other (or out-of-scope) procedures performed during these encounters.



• Can I perform State-level analyses with the NASS?
  
  Analysts cannot use the NASS to generate State-level estimates. The database includes the region in which each hospital-owned facility is located but does not identify the State. Because the sampling methodology used to create the NASS included region as a stratifier, researchers can use the NASS encounter weights to generate regional and national estimates from the raw counts.
  
  For information on State-specific ambulatory surgeries, we recommend that you work with the HCUP SASD.



• Are the NASS data weighted?
  
  NASS data purchased through the HCUP Central Distributor include encounter weights, which the user must apply to produce national estimates. To learn how to properly weight data, consult HCUP's free online tutorial called Producing National HCUP Estimates, which describes the process of applying the weights to your data.



• How often is the NASS released, and what years are available?
  
  The NASS is released annually, approximately 18 to 22 months after the end of a calendar year. Data years are available starting in 2016. Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog.



• How much does the NASS cost?
  
  Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog. Student pricing is available.

• What is the Nationwide Emergency Department Sample (NEDS)?
  
  The NEDS is the largest publicly available all-payer emergency department (ED) database in the United States, yielding national estimates of ED visits. Unweighted, the NEDS contains approximately 35.8 million records each year from about 1,000 EDs. Weighted, it estimates approximately 145 million ED visits. The NEDS contains discharges from more than 980 hospitals and approximates a 20 percent stratified sample of U.S. hospital-based EDs. It is constructed using records from (1) the HCUP State Emergency Department Databases (SEDD), which capture information on ED visits that do not result in an admission (i.e., treat-and-release visits and transfers to another hospital), and (2) the SID, which contain information on patients initially seen in the ED and then admitted to the same hospital. The NEDS includes ED charge information for approximately 87 percent of all U.S. ED visits, regardless of expected payer.
  
  The most recent version of the NEDS (data year 2018) includes discharges from 990 hospital-owned EDs in 36 States and the District of Columbia.
  
  Additional information on the NEDS, including a description of data elements and summary statistics, can be found on the NEDS Database Documentation page. The database can be purchased through the HCUP Central Distributor, and statistics from the database are available on HCUPnet.



• Does the NEDS contain ICD-9-CM/ICD-10-CM/PCS procedure codes or Current Procedural Terminology (CPT®) codes?
  
  The NEDS contains both types of procedure codes; however, the type of code(s) depends on the State and the type of ED visit. For ED visits that do not result in hospitalization, procedures may be reported as both ICD-9-CM/ICD-10-CM/PCS and CPT, Fourth Edition (CPT-4) procedure codes. Information on availability by State can be found under the Availability of Data Elements by Year link located on the SEDD Database Documentation page of the HCUP-US website. This information may vary by year, so please refer to the data year corresponding to the NEDS of interest.
  
  For ED visits resulting in hospitalization, procedures are coded as ICD-9-CM/ICD-10-CM/PCS codes but also are sometimes available in CPT codes. Information on availability by State can be found under the Availability of Data Elements by Year link located on the SID Database Documentation page of the HCUP-US website. This information may vary by year, so please refer to the data year corresponding to the NEDS of interest.



• Are the NEDS data weighted?
  
  NEDS data purchased through the HCUP Central Distributor include discharge weights, which the user must apply to produce national estimates. To learn how to properly weight data, consult HCUP's free online tutorial Producing National HCUP Estimates, which describes the process of weighting data.
  
  Please note that if you are using HCUPnet (our free, online query system), the weighting already has been applied—the statistics produced are national estimates.



• How often is the NEDS released, and what years are available?
  
  The NEDS is released annually, approximately 18 to 22 months after the end of a calendar year. Data years begin with 2006. Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog.



• How much does the NEDS cost?
  
  Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog. Student pricing is available.
  
  Additionally, statistics and data tables from the NEDS are available on HCUPnet, HCUP's free, online query system.

• What is the Nationwide Readmissions Database (NRD)?
  
  The NRD is the largest publicly available all-payer readmissions database in the United States that can be used to examine national estimates of readmissions. Unweighted, it contains approximately 18 million discharges each year. Weighted, it estimates approximately 35 million discharges. The NRD is drawn from SID containing verified patient linkage numbers that can be used to track a person across hospitals within a State.
  
  The most recent version of the NRD (data year 2018) includes data from 28 HCUP Partners. These States are geographically dispersed and account for 59.7 percent of the total U.S. population and 58.7 percent of all U.S. hospitalizations.
  
  Additional information on the NRD, including a description of data elements and summary statistics, can be found on the NRD Database Documentation page. The database can be purchased through the online HCUP Central Distributor, and select statistics from the databases are available on HCUPnet.
  
  
• How is the NRD different from the NIS?
  
  The NRD and the NIS differ in design and availability of data elements. The 2018 NRD uses the SID from 28 HCUP Partners with verified patient linkage numbers and includes discharges from community hospitals, excluding rehabilitation and long-term acute care hospitals. After certain exclusions, all discharges in the sampling frame were included, making the NRD a sample of convenience. The NIS contains a sample of records from each SID that can be weighted to represent national estimates. The NRD can be used to estimate national readmission rates for all-payers, and addresses a large gap in healthcare data—the lack of nationally representative information on hospital readmissions for all ages.



• How are readmissions defined in the NRD?
  
  The NRD is designed to be flexible to various types of analyses of readmissions in the United States for all patients, regardless of the expected payer for the hospital stay. The criteria to determine the relationship between multiple hospital admissions for an individual patient are left to the analyst using the NRD. Outcomes of interest include national readmission rates, reasons for returning to the hospital for care, and the hospital costs for discharges with and without readmissions.



• Can I perform State-level analyses with the NRD?
  
  The sampling methodology used to create the NRD does not include State as a stratifier; therefore, analysts cannot use the database to generate State-level estimates. Although the NRD includes weights to allow researchers to generate national estimates from the raw counts, no weights are included for the calculation of State-level estimates.
  
  For information on State-specific inpatient stays, we recommend that you work with the HCUP SID.



• Are the NRD data weighted?
  
  NRD data purchased through the HCUP Central Distributor include discharge weights, which the user must apply to produce national estimates. To learn how to properly weight data, consult HCUP's free online tutorial called Producing National HCUP Estimates, which describes the process of applying the weighting to your data.
  
  Please note that if you are using HCUPnet (our free, online query system), the weighting already has been applied—the statistics produced are national estimates.



• How often is the NRD released, and what years are available?
  
  The NRD is released annually, approximately 18 to 22 months after the end of a calendar year. Data years begin with 2010. Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog.



• How much does the NRD cost?
  
  Complete database availability and pricing information is included in the online HCUP Central Distributor Database Catalog. Student pricing is available.
  
  Additionally, statistics and data tables from the NRD are available on HCUPnet, HCUP's free, online query system.

• What are the State databases?
  
  HCUP's State databases are a collection of all-payer datasets from participating States that can be used to investigate State-specific and multi-state trends in healthcare utilization, access, charges, quality, and outcomes. The HCUP State databases consist of the State Inpatient Databases (SID), the State Ambulatory Surgery and Services Databases (SASD), and the State Emergency Department Databases (SEDD)..
  
  A summary table shows the availability of State-level data by database and year. Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog. Note that the 2015 State databases contain ICD-9-CM and ICD-10-CM/PCS codes. On October 1, 2015, hospital administrative data began using ICD-10-CM/PCS codes therefore, the first 9 months of 2015 contain ICD-9-CM codes, and the last 3 months contain ICD-10-CM/PCS codes. Data elements and the data structure for the 2015 State databases have changed. Trends based on diagnoses or procedures will be affected.
  
  Statistics from select States and settings are available on HCUPnet. Please review HCUPnet for a list of participating States and their years of participation.



• Do I need to weight my State database data?
  
  HCUP's State databases do not need to be weighted. HCUP's State databases provide a census (not an estimate) of inpatient stays, ambulatory surgery encounters, or emergency department encounters occurring in a State's community hospitals. For additional information, please review the HCUP Methods Series Report #2010-05: Inferences With HCUP State Databases Final Report (PDF file, 215 KB).
  
  
• If a State is an HCUP Partner, why are its databases not available through the HCUP Central Distributor or on HCUPnet?


HCUP Partners decide whether to distribute their State-level, public-release databases through the HCUP Central Distributor and whether to distribute statistics on HCUPnet. As a result, data from any given State may be available through one or both sources, and the years of participation can vary.

A summary table shows State participation in the HCUP Central Distributor by database and year. Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog. HCUPnet provides a list of the available State statistics and years included in the query system on the State statistics pathways.

If a State of interest does not release its full dataset through the HCUP Central Distributor or participate in HCUPnet, contact the HCUP Partner directly for information about the availability of that State's data.


• When are the State databases generally released?
  
  HCUP's State databases (SID, SASD, and SEDD) are released on a rolling basis—typically beginning 6 to 9 months following the end of a calendar year.
  
  A summary table shows the availability of State-level data by database and year. Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog. Recent releases also are noted on a monthly basis in the HCUP Database and Product Releases Calendar.

• What are the State Inpatient Databases (SID)?
  
  The SID are a set of all-payer inpatient care databases from participating HCUP Partners that capture hospital inpatient stays in a given State. They contain the universe of inpatient discharge abstracts in participating States that are translated into a uniform format to facilitate multi-state comparisons and analyses. The SID contain a core set of clinical and nonclinical information on all patients, regardless of expected payer.
  
  Together, the SID encompass about 97 percent of all U.S. community hospital discharges.
  
  The SID are the building blocks of the NIS, the KID, the NRD, and the NEDS. All SID include a core set of variables that commonly are included on inpatient discharge abstracts, along with some State-specific data elements.
  
  Additional information on the SID, including a description of data elements with participation by State and year and summary statistics for select States, can be found on the SID Database Documentation page. Select SID can be purchased through the HCUP Central Distributor, and statistics from select States are available on HCUPnet.



• What is the difference between the SID and the NIS?
  
  The SID and the National Inpatient Sample (NIS) differ in design and availability of data elements. The SID contain the universe of the inpatient discharge abstracts in participating States. The NIS contains a sample of records from each SID that can be weighted to represent national estimates. Key differences exist between the SID and the National Inpatient Sample (NIS). Foremost, each SID contains the universe of inpatient discharge abstracts provided by an HCUP State Partner, whereas the NIS consists of a sample of discharges provided by all HCUP State Partners. Additionally, the NIS contains fewer data elements than the SID. The common data elements in the SID become the NIS core data elements and are standardized.



• What years of the SID are available, and how much do they cost?
  
  The availability and cost of the SID vary by State and year. The earliest available SID begin in 1990; however, not all States provide data from every year. Each HCUP Partner sets its own pricing, and some charge by applicant affiliation. A summary table shows the availability of State-level data by database and year. Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog.
  
  Additionally, statistics and data tables from select SID are available on HCUPnet, HCUP's free, online query system.
  
  Many HCUP Partners participate in the HCUP Central Distributor and HCUPnet; however not all do. To obtain State-level data from a State that does not participate, contact the HCUP Partner directly for information on the availability of that State's data.

• What are the State Ambulatory Surgery and Services Databases (SASD)?
  
  The SASD include encounter-level data for ambulatory surgeries and also may include data on various types of outpatient services such as observation stays, lithotripsy, radiation therapy, imaging, chemotherapy, and labor and delivery. The specific types of ambulatory surgery and outpatient services included in each SASD vary by State and data year. All SASD include data from hospital-owned ambulatory surgery facilities. In addition, some States include data from facilities not owned by a hospital. The designation of a facility as hospital-owned is specific to its financial relationship with a hospital that provides inpatient care and is not related to its physical location. Hospital-owned ambulatory surgery and other outpatient care facilities may be contained within the hospital, physically attached to the hospital, or located in a different geographic area.
  
  The 2015 SASD contain ICD-9-CM and ICD-10-CM/PCS codes. On October 1, 2015, hospital administrative data began using the ICD-10-CM/PCS coding system, so the first 9 months of 2015 contain ICD-9-CM codes, whereas the last 3 months contain ICD-10-CM/PCS codes. Data elements and the data structure for the 2015 SASD have changed. Trends based on diagnoses or procedures will be affected.
  
  Additional information on the SASD, including a description of data elements with participation by State and year and summary statistics for select States, can be found on the SASD Database Documentation page. Select SASD can be purchased through the HCUP Central Distributor, and statistics from select States are available on HCUPnet.



• What types of facilities are included in the SASD?
  
  All SASD include data from hospital-owned ambulatory surgery facilities. In addition, some States include data from nonhospital-owned facilities. The designation of a facility as hospital-owned is specific to its financial relationship with a hospital that provides inpatient care is not related to its physical location. Hospital-owned ambulatory surgery and other outpatient care facilities may be contained within the hospital, physically attached to the hospital, or located in a different geographic area. The designation as hospital-owned means that HCUP can identify that the hospital is billing for this service. A complete list of the types of facilities included in the SASD can be found on the SASD File Composition page.



• What years of the SASD are available, and how much do they cost?
  
  The availability and cost of the SASD vary by State and by year. The earliest available SASD begin in 1997; however, not all States provide data from every year. Each HCUP Partner sets its own pricing, and some charge by applicant affiliation. A summary table shows the availability of State-level data by database and year. Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog.



• What is the difference between the State Ambulatory Surgery Databases (for years prior to 2014) and the State Ambulatory Surgery and Services Databases (for 2014 onward)?
  
  The State Ambulatory Surgery and Services Database replaces the State Ambulatory Surgery Databases for years starting 2014. The only difference between the two databases is the name and both are referred to as SASD. The name State Ambulatory Surgery and Services Databases (SASD) better describes the current and historical content. There is no difference in the sampling or variables available in the SASD database before and after the name change.
  
  The HCUP team has endeavored to better understand the types of data and utilization that are included in the State Ambulatory Surgery Databases (SASD). We completed a rigorous review of all documentation that is provided by our HCUP Partners, supplemented by phone conversations with each of the Partner data organizations that provide State Ambulatory Surgery Databases data to HCUP. It is clear that for most of our Partners, the State Ambulatory Surgery Databases include data for outpatient ambulatory surgery as well as other hospital-based outpatient services. Some of our HCUP Partners also provide ambulatory surgery data and outpatient care services from nonhospital-owned facilities. Therefore, we have updated the name of the databases to the State Ambulatory Surgery and Services Databases (the acronym SASD will stay the same) and updated all documentation on HCUP-US to better communicate what is included in these databases. Visit the SASD Overview page for additional information.

• What are the State Emergency Department Databases (SEDD)?
  
  The SEDD are a set of all-payer emergency department (ED) databases from participating HCUP Partners that capture discharge information on all ED encounters that do not result in an admission to the same facility. They include a universe of abstracts from hospital-owned ED encounters from community hospitals. Composition and completeness of the variables in the file may vary from State to State. The SEDD contain a core set of clinical and nonclinical information on all patients, regardless of expected payer.
  
  Additional information on the SEDD, including a description of data elements with participation by State and year and summary statistics for select States, can be found on the SEDD Database Documentation page. Select SEDD can be purchased through the HCUP Central Distributor, and statistics from select States are available on HCUPnet.



• Do the SEDD include all ED encounters—both those in which the patient was admitted and those in which the patient was treated and released?
  
  No. The SEDD provide encounter-level information for ED encounters that do not result in an admission to the same facility (i.e., patients in the SEDD were treated and released). Records for inpatient stays that began in the ED are found in the SID. Both the SEDD and SID are needed to analyze all ED encounters in a State.



• What years of the SEDD are available, and how much do they cost?
  
  The availability and cost of the SEDD vary by State and by year. The earliest available SEDD begin in 1999; however, not all States provide data from every year. Each HCUP Partner sets its own pricing, and some charge by applicant affiliation. A summary table shows the availability of State-level data by database and year. Complete database availability and pricing information is provided in the online HCUP Central Distributor Database Catalog.
  
  Additionally, statistics and data tables from select SEDD are available on HCUPnet, HCUP's free, online query system.
  
  Many HCUP Partners participate in the HCUP Central Distributor and HCUPnet; however, not all do. To obtain State-level data from a State that does not participate, contact the HCUP Partner directly for information about the availability of that State's data.

• How can I access data or statistics from HCUP?
  
  The HCUP databases are available for purchase online through the HCUP Central Distributor. All purchasers must complete the online HCUP Data Use Agreement (DUA) Training and create an HCUP Central Distributor user account in order to submit an application to purchase HCUP data. Please see Purchasing FAQs for additional information.
  
  Statistics and data tables from HCUP's nationwide and select State databases can be obtained from HCUPnet, a free, online query system. Statistics and data tables on select topics are also available through HCUP Fast Stats.
  
  HCUP is a voluntary partnership between the Federal government and State data organizations (HCUP Partners). Each Partner determines how its data are used in HCUP; thus, not all States participate in the HCUP Central Distributor, HCUPnet, and/or Fast Stats.



• Can I obtain a customized dataset or access additional elements that are not included in the standard HCUP databases?
  
  HCUP does not offer customized datasets—the data are offered as standard databases. No elements beyond those that already are included in the standard databases are available to the public.

• How do I contact the HCUP Central Distributor?
  
  Email: HCUPDistributor@ahrq.gov (include order number in subject line if applicable)
  Phone: 866-556-HCUP (4287) (toll free)
  Fax: 866-792-5313 (toll free in the United States)
  
  Mailing address:
  HCUP Central Distributor
  Social & Scientific Systems, a DLH company
  8757 Georgia Ave, 12th Floor Silver Spring, MD 20910

• How do I purchase HCUP databases, and how much do they cost?
  
  HCUP Nationwide Databases and HCUP State Databases are available for purchase online through the HCUP Central Distributor by applicants who complete the HCUP Data Use Agreement (DUA) Training and sign an HCUP DUA. Complete pricing and availability and can be found online in the HCUP Central Distributor Database Catalog.
  
  Each HCUP Partner determines the availability and pricing for their data. A summary table shows the Availability of HCUP Databases Across States and Years. Some Partners may place additional restrictions on the sale of their data. Many HCUP Partners participate in the HCUP Central Distributor, but not all do. If a State of interest does not release its data through the Central Distributor, you may contact the HCUP Partner directly for information about the availability of that State's administrative data.



• What HCUP databases are available for purchase?
  
  The HCUP nationwide databases and select State databases are available for purchase. Refer to the Nationwide Databases section of these FAQs for information about the National (Nationwide) Inpatient Sample (NIS), the Kids' Inpatient Database (KID), the Nationwide Ambulatory Surgery Sample (NASS), the Nationwide Emergency Department Sample (NEDS), and the Nationwide Readmissions Database (NRD). Refer to the State Databases section of these FAQs for information about the State Inpatient Databases (SID), the State Ambulatory Surgery and Services Databases (SASD), and the State Emergency Department Databases (SEDD). Complete database availability and pricing information is provided online in the HCUP Central Distributor Database Catalog.



• When are HCUP databases generally released?
  
  Database releases are listed in the HCUP Database and Product Release Calendar as they become available for purchase through the HCUP Central Distributor Database Catalog.
  
  Typical release schedules for the HCUP nationwide and State databases are discussed in these FAQs in the Nationwide Databases section and the State Databases sections, respectively.



• Are the HCUP Supplemental Files included with the databases?
  
  HCUP supplemental files are hospital-level or discharge-level files that augment the information contained in the HCUP nationwide and State databases. Refer to the HCUP Supplemental Files section of the Tools & Software page for detailed information about the types of supplemental files available. Supplemental files are available to HCUP data users free of charge.
  
  Most supplemental files may be downloaded from the HCUP-US website. The following three supplemental file types are ordered online through the HCUP Central Distributor Database Catalog:
  
  
  • HCUP Cost-to-Charge Ratio (CCR) Files: hospital-level files designed to supplement the data elements in the NIS, KID, NEDS, NRD, SID, and SEDD. When you add a NIS, KID, NEDS, or NRD database to your shopping cart, the complimentary CCR supplemental file applicable to that database will automatically be added to the shopping cart, but can be removed if not needed. The CCR files for the SID or SEDD are not automatically added to the cart when SID or SEDD databases are ordered, but may be selected from the catalog and added to the cart.
  
  
  • HCUP Hospital Market Structure (HMS) Files: hospital-level files designed to supplement the data elements in the NIS, KID, and SID. HMS Files are not automatically added to the shopping cart when applicable databases are ordered, but may be selected from the catalog and added to the cart.
  
  
  • 1993-2002 Nationwide Inpatient Sample (NIS) Supplemental Discharge-Level Files: discharge-level files that provide the NIS data user with the trend weights and data elements that are consistently defined across data years. The file appears as "NIS Discharge Lvl 1993-2002 " in the catalog and is not automatically added to the shopping cart when applicable years of the NIS are ordered.

• Where do I log in to my HCUP Central Distributor account?
  
  The online HCUP Central Distributor page contains a log in link in the upper right banner area.
  
  After logging in, you will see additional links under "My Account" for activities including viewing and updating your account information, submitting DUAs online, checking the status of data purchase applications, downloading your purchased nationwide databases, and submitting data re-use requests for State-level databases in your custody.



• Is an account required to purchase HCUP data?
  
  Yes, you must have an account with the online HCUP Central Distributor to submit an application to purchase HCUP data. You can browse the Database Catalog for available HCUP products and add items to the shopping cart without an account; however, you cannot proceed to checkout without logging in to your account. The online HCUP Central Distributor provides links to register, log in, complete your account profile (including proof of DUA training), and return to your shopping cart when ready.



• How do I set up an account?
  
  
  • Take the required online HCUP Data Use Agreement (DUA) Training. Document the certification code provided upon completion and the completion date. This information will be required to complete your account registration. For more information see "Why is Data Use Agreement (DUA) training required for account setup?" below.
  
  
  • Register for an account with the online HCUP Central Distributor. You will be asked to provide your first and last names, your email address (which will be used as your username) and a password.
  
  
  • Login in to the online HCUP Central Distributor page and complete your user profile under My Account, including your DUA training certification code and completion date.



• Why is Data Use Agreement (DUA) training required for account setup?
  
  All purchasers and users of HCUP data must complete the online HCUP Data Use Agreement (DUA) Training so that they are familiar with the rules and restrictions for use of HCUP data. It is imperative to understand how the data may be used before placing your order or gaining access to HCUP data.
  
  As an account holder who has taken the DUA training, you will be eligible to submit applications for purchasing HCUP data, submit requests for re-using your HCUP data for new projects, and collaborate on another account holder's HCUP data project. You will be required to execute a current Data Use Agreement for each purchase and each project being considered.



• Can I set up an account and order databases on someone else's behalf?
  
  The data purchaser takes full responsibility for complying with all terms of the Data Use Agreement. Consequently, the account holder cannot order databases for, or ask the Central Distributor to ship databases to, someone else. Databases must be received by the data purchaser, who has agreed to the terms of the DUA and is responsible for the data.
  
  Under the terms of the DUA, the data purchaser remains responsible for the security and use of the HCUP data unless and until custody of the data officially is transferred to another individual. This and other Responsibilities of the Data Purchaser (PDF file, 33 KB) are acknowledged during database purchase. To transfer custody of HCUP databases, the original data purchaser must agree to relinquish his or her rights to the data and the new data custodian must complete the HCUP DUA Training course; read, sign, and submit the appropriate HCUP DUA; and agree to take full responsibility of the HCUP databases as described in the DUA. To request a transfer of custody, contact the HCUP Central Distributor.



• Are other people working on my study required to submit a Data Use Agreement?
  
  Yes. Anyone with access to HCUP data or access to results from the data that contain sensitive information (such as information by individual hospitals or aggregated statistics with small cell sizes) must complete the HCUP Data Use Agreement (DUA) Training and sign the DUA for nationwide and/or state databases. Both the signed DUA(s) and the HCUP DUA Training completion certificate (or certification code) must be submitted to the HCUP Central Distributor before any collaborator can be granted access to the data.



• How do I submit my Data Use Agreement?
  
  Data Purchasers:
  Data users purchasing HCUP databases and supplemental files through the online HCUP Central Distributor will execute their DUAs electronically during the ordering process. Purchasers must review and acknowledge the DUA to place an order. A copy of the executed DUA will be available under My Account. Please note that users are required to sign and submit a Nationwide DUA or State DUA each time they complete a new application to purchase HCUP databases.
  
  Others With Access to HCUP Data:
  Anyone with access to HCUP data must complete the online HCUP Data Use Agreement (DUA) Training and submit proof of training with the appropriate DUA(s) prior to gaining access to the data. The following options for submitting DUAs are detailed under the Data Use Info & Agreements tab of the online HCUP Central Distributor.
  • DUAs can be electronically acknowledged and submitted through the online HCUP Central Distributor by data users with proof of DUA training. A copy of the executed DUA will be available under My Account.
  • If you will be working on a specific project, ask your data custodian (the person whose data you will access) to issue you an electronic invitation to submit the DUAs online. Using the invitation will streamline the online DUA submission process and ensure that your DUAs are associated with the correct data custodian.
  • If you cannot access the online HCUP Central Distributor, proof of training and signed DUAs may be submitted by fax or postal service.



• How do my collaborators submit their signed Data Use Agreements (DUAs) and DUA training certificates?
  
  Before you may share your HCUP data with anyone, the data user must complete the HCUP Data Use Agreement (DUA) Training and read and sign the applicable Nationwide DUA and/or State DUA found on the DUA Training page. These documents must be submitted to the HCUP Central Distributor before you grant access to your HCUP databases.
  
  The following options for submitting DUAs are detailed under the Data Use Info & Agreements tab in the online HCUP Central Distributor:
  • DUAs can be electronically acknowledged and submitted through the online HCUP Central Distributor by data users with proof of DUA training. A copy of the executed DUA will be available under My Account.
  • You may issue invitations to your data users to streamline the online submission process using the online HCUP Central Distributor under the DUAs tab in My Account.
  • If your data user cannot access the online HCUP Central Distributor, proof of training and signed DUAs may be submitted by fax or postal service.



• Is a Data Use Agreement different from a Statement of Intended Use, and do I need both?
  
  The Nationwide and State Data Use Agreements define the rules and limitations under which any HCUP data may be used; a DUA is required for every person with access to the data regardless of the nature of the project.
  
  State-level HCUP data also requires a Statement of Intended Use (PDF file, 45 KB) which defines your specific project plans. AHRQ and the HCUP Central Distributor facilitate access to the State-level HCUP data (i.e., SID, SASD and SEDD), which are owned and regulated by the individual Data Organizations participating in HCUP. Under AHRQ's agreements with these Data Organizations, AHRQ reviews and approves all intended uses of the State-level data on their behalf. See "Why am I being asked to provide a Statement of Intended Use and what should I include in my statement?" for more information.
  
  
• Can I re-use my HCUP State data for a new project?
  
  Each application for and approval of HCUP data is project-specific. If the data will be used for a purpose other than that for which it originally approved, or as concrete projects emerge from approved exploratory work, the data custodian must submit a "Data Re-use Request" through the online HCUP Central Distributor for review and approval by AHRQ before work may begin on the new project. Data re-use requests are submitted and managed through the State Data Re-Use tab under My Account.
  
  
• If I change my email address, will my HCUP account Username change, too?
  
  If you need to change your email address, you may do so without affecting the original "Username" that was set up when you registered with the online HCUP Central Distributor. Your email address can be updated on the User Information tab under My Account. It also can be updated while confirming your Applicant Information during order checkout. Your Username will not change.

• How long will items be saved in my shopping cart?
  
  Items will be saved in your online HCUP Central Distributor shopping cart for 30 days. After 30 days, items automatically will be removed from your cart.



• Why am I being asked to provide a Statement of Intended Use, and what should I include in my statement?
  
  A Statement of Intended Use (PDF file, 45 KB) is required if you requested SID, SASD, and/or SEDD files from the HCUP Central Distributor. This statement is reviewed by AHRQ on behalf of the HCUP Partners. It should include enough information for reviewers to understand the subject area of interest, how the data will be used, level of analysis, intended audiences, and anticipated end products (e.g., tables and charts, internal reports, peer-reviewed journal articles), as well as to demonstrate understanding of and compliance with the HCUP Data Use Agreement (DUA). In some cases, the HCUP Partners also review the Statement of Intended Use before approval is granted, and in all cases, orders that include State databases are provided in full to the respective data organizations.
  
  The AHRQ reviewers will place your application on hold and request clarification from you if your Statement of Intended Use is insufficient for review and approval.



• How can I view the Statement of Intended Use that I submitted for my State database order?
  
  The Statement of Intended Use submitted with your order is included on your invoice. To access all details of your data request including invoice, Data Use Agreements, Statement of Intended Use, and current status, log in to the online HCUP Central Distributor and view the Orders tab under My Account. The Statement of Intended Use will also appear on the copy of your invoice that is included in each email you receive from the HCUP Central Distributor (Do-Not-Reply-HCUPDistributor@s-3.com) as your order is processed.
  
  Please note that if the Statement of Intended Use that you submit with your order does not provide enough information for the AHRQ reviewers to understand how you intend to use and secure the HCUP data, you will receive instructions via email on how to edit and resubmit your Statement of Intended Use online.
  • For applications submitted after October 17 2018, the Statement of Intended Use viewed in your order details will reflect your online revisions and AHRQ's project-specific approval when applicable.
  • For orders submitted prior to October 17, 2018, any email or telephone communications that further clarified the scope of the project and use of the HCUP data are not reflected in the static Statement of Intended Use captured with the original application, but nonetheless are deemed to govern and/or limit the extent of the approved use of the data.



• Can I place an order without electronically acknowledging the Data Use Agreement, Responsibilities of the Data Purchaser, and Indemnification Clause?
  
  Every order requires the data purchaser to read and agree to the terms of the applicable HCUP Data Use Agreement (DUA), Responsibilities of the Data Purchaser, and Indemnification Clause. If you place your order online, you must execute these agreements electronically as a part of the checkout process; you will not be able to complete your order without doing so.
  
  If you or your institution requires a physically signed DUA, you will need to submit a hard copy application for your order. Please contact the HCUP Central Distributor for assistance.
  
  
• How do I print my order invoice and the acknowledged Data Use Agreement(s), Responsibilities of the Data Purchaser, and Indemnification Clause associated with my order?
  
  To access all details of your data request including invoice, Data Use Agreement, Responsibilities of the Data Purchaser, Indemnification Clause, Statement of Intended Use, and current status, log in to the online HCUP Central Distributor and view the Orders tab under My Account.



• Can I have the data delivered to someone else?
  
  No. The account holder takes full responsibility for complying with all terms of the Data Use Agreement and the Responsibilities of the Data Purchaser (PDF file, 33 KB). HCUP data may only be delivered to (i.e., shipped to or downloaded by) the individual who places the order through his or her account. Consequently, the account holder cannot order databases for, or authorize their delivery to, someone else. See Can I set up an account and order databases on someone else's behalf? for more information.



• How can I tell if my order was received?
  
  When you are completing your HCUP database order through the online HCUP Central Distributor, after selecting Order now to submit your order, you will be directed to a page confirming that the order was submitted and explaining what to expect in the order fulfillment process.
  
  You will receive follow-up emails from the HCUP Central Distributor (Do-Not-Reply-HCUPDistributor@s-3.com) containing your order invoice, order status updates, and all necessary instructions for order fulfillment.



• How long will it take to receive the HCUP database(s) I ordered?
  
  HCUP nationwide databases (NIS, KID, NASS, NEDS, and NRD) and related supplemental files are delivered via digital download only. They can be downloaded through the online HCUP Central Distributor after your order is approved and you are notified that your products have been activated for download. You will receive detailed instructions via email. Please be aware that download links are active for only 7 days.
  
  HCUP State databases (SID, SASD, and SEDD) and related supplemental files are shipped on CD/DVD, typically within 5-7 business days after the order is approved by AHRQ on behalf of the HCUP Partners. In some cases, additional review by the Partner organization will be required and may increase the time needed to respond to applications. Payment must also be complete before the order will ship. The HCUP Central Distributor uses FedEx® Standard Overnight® service. An adult signature is required to receive the package.



• How can I check the status of my order?
  
  To access all details of your data request, log in to the online HCUP Central Distributor and view the Orders tab under My Account. The current status of your order is displayed.
  
  Orders are processed after payment and any applicable documentation (such as verification of eligibility for student or non-profit pricing) are received by the HCUP Central Distributor. You will receive email status updates from the HCUP Central Distributor (Do-Not-Reply-HCUPDistributor@s-3.com).
  
  If you paid by credit card, please note that credit card authorization expires after 30 days. Your card will not be charged until the databases are shipped or activated for download. Orders that include State databases or discount pricing require time for review and processing, and may require additional action on your part. Please respond promptly to any inquiry from the HCUP Central Distributor regarding your order.
  
  If you have questions about the status, please contact the HCUP Central Distributor.



• How do I change or cancel my order?
  
  For any changes or to cancel your order, you must contact the HCUP Central Distributor. Please include your order number for reference. The order number is in the subject line of each email you have received from the HCUP Central Distributor, and can be viewed on the Orders tab under My Account in the online HCUP Central Distributor.

• Am I eligible to order California "Single Use" files?
  
  Eligibility and other restrictions and limitations on purchasing the California SID, SASD, and SEDD beginning with data year 2018 are defined in the Additional Requirements from the State of California (PDF file, 92 KB; HTML). Briefly, applicants must be academic researchers employed by a college or University located in the United States or a US territory whose project has undergone review by their academic institution's Institutional Review Board (IRB). Further limitations on the project and intended use apply; refer to the Additional Requirements from the State of California for the full terms.
  
  For questions about these California-specific data use restrictions, please contact DataandReports@OSHPD.CA.gov.



• What is a California "Single Use" file?
  
  California SID, SASD, and SEDD beginning with data year 2018 carry Additional Requirements from the State of California (PDF file, 92 KB; HTML) defined by the California Office of Statewide Health Planning and Development (OSHPD). Regarding the "single-use" project requirement, these limitations include:
  
  • The data may only be used for the project described in the application. This project must have undergone review by your academic institution's Institutional Review Board (IRB) prior to application submission.
  
  
  • The approved use of these files expires three years after the order was submitted. At the end of the three years, you will be required to certify the destruction of the databases or obtain an extension from the OSHPD. Please refer to the Additional Requirements from the State of California document for details and contact information for the OSHPD.



• Why do the 2018 and later data year California SID, SASD, or SEDD files have to be ordered separately from other files?
  
  California SID, SASD, and SEDD databases beginning with data year 2018 carry Additional Requirements from the State of California (PDF file, 92 KB; HTML) defined by the California Office of Statewide Health Planning and Development (OSHPD) that do not apply to any other HCUP databases. These files must be ordered separately to facilitate collection of the acknowledged Additional Requirements document and management of the "Single Use" file expiration.



• When will I be required to acknowledge the Additional Requirements from the State of California?
  
  When you request any California SID, SASD, and SEDD databases beginning with data year 2018, you will be required to confirm that you are eligible for them and that you agree to the Additional Requirements from the State of California (PDF file, 92 KB; HTML) governing their use. These files carry specific requirements and limitations defined by the California Office of Statewide Health Planning and Development (OSHPD). Please review these Additional Requirements before requesting the 2018 and later CA files.
  
  For questions about these California-specific data use restrictions, please contact DataandReports@OSHPD.CA.gov.



• Am I eligible to order Georgia files?
  
  Georgia data is not available for purchase by for-profit entities or students.



• I see in the database catalog that "The Georgia Hospital Association must approve any data release." Will that delay my order?
  
  Following AHRQ review of all applications that include any Georgia database, the application is forwarded to the Georgia Hospital Association for review. The Georgia Hospital Association reviews and must approve any request for GA HCUP files. AHRQ cannot guarantee the timeliness of responses from outside organizations. Further, the HCUP Central Distributor cannot partially fill or split orders, so if your order includes GA data, your entire order will be put on hold until the GA Partner provides guidance to AHRQ. If your project involves data from additional States and is particularly large or time-sensitive, you may wish to submit a separate order for the GA files.



• Why didn't I receive Iowa, Minnesota, or Nebraska AHA Linkage files with my order?
  
  HCUP Partners control the availability of American Hospital Association (AHA) Linkage files for their State data. Iowa, Minnesota, and Nebraska restrict the distribution of AHA Linkage files to purchasers whose organizational affiliation and ownership meet the Partner's eligibility criteria. Please refer to the AHA Linkage Files page for eligibility details.
  
  If you are eligible for these AHA linkage files and your organizational affiliation is correctly identified in your user account profile in the online HCUP Central Distributor, you should receive the AHA Linkage files with your State database order for Iowa, Minnesota, and/or Nebraska. If you did not receive these AHA Linkage files with your order and believe you meet the eligibility criteria, contact the HCUP Central Distributor to verify that your account profile is correctly defined and to request the files.
  
  All other available AHA Linkage files are downloaded from the AHA Linkage Files page.

• Why are there different price categories for many HCUP databases?
  
  The HCUP nationwide databases (NIS, KID, NASS, NEDS, and NRD) are offered at a discounted price for students. In addition, several States offer student prices for their HCUP State databases (SID, SASD, and SEDD).
  
  Part-time and full-time students at any stage in their training are eligible for the published student prices on HCUP data purchased for the student's exclusive use. However, all students must demonstrate their current student status by providing (1) a copy of a valid student ID or (2) a letter from the registrar's office, a professor advisor, or the program director. This information must be submitted to the HCUP Central Distributor (contact the HCUP Central Distributor) after you place your order. Your application will not be reviewed by AHRQ until proof of eligibility for student pricing has been provided. For more information, see If an HCUP database is purchased at student pricing for a student/faculty project, is the faculty member allowed to continue using the database after the student leaves?.
  
  Some States also offer other pricing categories such as those for nonprofit affiliations and AHRQ grantees. If your order is based on these pricing categories, you may be asked to provide documentation of affiliation or AHRQ grantee status before your order may be fulfilled.



• Will I be charged for shipping costs?
  
  Shipping and handling costs are included in the price of the databases. Customs and other duty charges for overseas delivery are not included. The HCUP Central Distributor does not calculate or collect duties or overseas taxes.



• Will taxes be applied to my order?
  
  The HCUP Central Distributor collects applicable State sales tax on orders shipped to Georgia, Maryland, and North Carolina. Individuals shipping to all other locations are responsible for determining tax liability and remitting taxes directly to State and local taxing authorities.



• What payment methods are accepted?
  
  The HCUP Central Distributor accepts payments from MasterCard® and Visa®, bank check, or wire transfer. You may select "Purchase order" as a payment method if applicable.
  
  Databases will not be shipped or activated for download until payment is received. Please contact the HCUP Central Distributor with payment. The order number or a copy of the invoice must be included with payment.
  
  
  • If payment is made online by credit card, your card will not be charged until the database(s) are shipped or activated for download. Credit card authorization expires after 30 days; please respond promptly to any inquiry from the HCUP Central Distributor regarding your order.
  • All other payments are submitted via phone, fax, or postal service as instructed in order status emails. The order number or a copy of the invoice must be included with payment.
  • Checks should be payable to Social & Scientific Systems, Inc.
  • Wire transfer or credit card information may be submitted by phone, fax, or postal mail. Do not email wire transfer or credit card information.
  • Purchase orders may be paid by check, credit card, or wire transfer.



• Does the HCUP Central Distributor retain my credit card information?
  
  No, the HCUP Central Distributor does not retain credit card information; only the card authorization is saved. Authorize.net is used as the payment gateway for processing credit card transactions. Authorize.net is on Visa's Global Registry of Payment Card Industry Data Security Standard (PCI DSS) Validated Service Providers. For credit card processing, only the Transaction ID and Authorization Code from Authorize.net are stored.
  
  Credit card authorization expires after 30 days. Please respond promptly to any inquiry from the HCUP Central Distributor regarding your order.



• If an HCUP database is purchased at student pricing for a student/faculty project, is the faculty member allowed to continue using the database after the student leaves?
  
  No, student purchases of HCUP data are specific to the student, they are intended for student-directed projects (e.g., dissertation), and the student is responsible for the security and all uses of the data. Faculty may be involved with the student's project (e.g., faculty advisor) and may have access to the data as long as they have completed the online HCUP Data Use Agreement (DUA) Training, read and signed the DUA, and submitted the training certification code and DUA to the HCUP Central Distributor, but student-priced databases are not intended for faculty-led projects in which the student is participating.
  
  Further, when the student leaves the university, the student must take the data with him or her; no one else is allowed independent access. A faculty member can have continued access to the data only if he or she continues to have a professional relationship with the student (e.g., coauthor or partners on a joint project). In that case, the student must agree to this collaboration because the student is held responsible for the data.

• Where do I go to download the nationwide database files I purchased?
  
  HCUP nationwide databases (NIS, KID, NASS, NEDS, and NRD) and related supplemental files are delivered in compressed, password-encrypted "zip" format via digital download. Each product's zip file is downloaded from the online HCUP Central Distributor under My Account > Orders > Database Downloads, after you are notified that your products have been activated for download. You will receive detailed instructions, including passwords, via email. Please be aware that download links are active for only 7 days.



• How long will it take to download the nationwide databases I purchased?
  
  Download performance depends on several highly variable factors, including the following:
  
  
  • Your internet connection speed and bandwidth
  • Global and regional internet traffic demand at the time of your download
  • Other users' demand on your network or internet service provider (ISP) resources at the time of your download
  
  In download performance trials from various locations across the United States and the United Kingdom, most test users completed a 1500 MB download in 10-20 minutes. The fastest networks download this large file in 3-8 minutes; the slowest download took 3 hours. Each user found the time to vary significantly between tests, depending on variable environmental factors.
  
  For optimal download performance, try to control the following variables to the extent possible:
  
  
  • Use a wired connection (e.g., Ethernet cable) if possible. Wired is much faster than wireless on the same network/internet service.
  • Avoid 'sleep' mode: Make sure your computer is not set to go to sleep. The download will be paused if your computer goes to sleep but can be resumed upon waking.
  • Use times of low demand on your network or local internet service provider (e.g., at work, try the download in the evening; at home, avoid evenings when other users of your ISP are likely to be online).
  • Avoid high-demand sites or activities on your computer during the download.
  • Avoid Virtual Private Networks (VPNs): If you use a VPN to connect to a secure work environment but could connect to the online HCUP Central Distributor directly (using a secure private/home or work network) while the VPN is not running, do so. VPNs significantly slow download speeds.
  
  You can check your internet connection speed/bandwidth at a given point in time using a site such as Bandwidth Place. Typical benchmarks are provided below:
  
  
  • Wired, no VPN: 26 MB per second
  • Wireless, no VPN: 18 MB per second
  • VPN, wired or wireless: 3 MB per second



• Is the database download process secure?
  
  Yes. You must be logged in to the online HCUP Central Distributor to initiate a download of purchased files under My Account > Orders > Database Downloads. The site uses secure socket layer (SSL) protocol; therefore, as long as you are using a secure network at work or home to log in, the download is secure. In addition, the files are compressed using an encrypted zip method which requires a password to unzip.
  
  However, as with any other internet activity involving private or restricted information, the download should not be performed over a public network.



• My download did not successfully complete and/or my download link is not working. What should I do?
  
  For each nationwide database you have purchased, the download link in the online HCUP Central Distributor will be valid for 7 days and is limited to three download attempts. If your download link has expired, you have received an error message indicating there was a problem with the download, or you have experienced any other problem preventing you from successfully downloading your products, please contact the HCUP Central Distributor for assistance in identifying and resolving the problem.
  
  Please make every effort to seek assistance before your download link expires.



• How can I tell if the file is downloading?
  
  The Download link initiates the browser's download widget, so the appearance and behavior of the download depends entirely on the internet browser you are using.
  
  To facilitate the process in any browser, if you are prompted to choose between Save and Open, choose Save. Be sure to save to a location that has enough space to hold the file(s) you are downloading. Some browsers may simply default to a Downloads folder or comparable default location. Some browsers have highly visible download prompting and progress displays, whereas other browsers may use download defaults and/or subtle progress displays. It is up to the user to be familiar with the download behaviors of the chosen internet browser.
  
  Contact the HCUP Central Distributor for assistance if you are unable to verify a successful download.



• How much space will the downloaded file(s) require?
  
  The size of each purchased file will be listed in your order on the online HCUP Central Distributor under My Account > Orders > Database Downloads. The compressed database files range from 300 MB to 2 GB when downloaded, as shown in the table below.
  
  Each product you download will contain several files when unzipped, including the core database file in comma-delimited or ascii format, additional database files such as hospital or severity files, and support files such as database documentation. The amount of space required to unzip each database product is shown in the table below, based on the largest year of data for each database type.

Please note that you will need SAS®, SPSS®, Stata®, or similar analysis software for processing the data, and all such processing requires several times as much disk capacity as the core file to perform typical processing steps. Because of variations in processing methods, analysis software varies greatly in how much disk space will be required. The amount of disk space required by your project will depend on which analysis software you are using, which database is involved, and the number of elements you use from the database.

To determine minimum data analysis space requirements, please refer to the documentation for each specific database you will be using. Database documentation can be found on the Databases page of the HCUP-US website.


• I already own a nationwide database. May I use the download feature to access the file?
  
  If your order was placed prior to March 1, 2016, there is no download capability for that order. The nationwide database download feature is available only for orders placed on or after March 1, 2016, and only for the initial download of your purchased product(s). It is your responsibility to store your purchased products securely for future use.

• Why do I get an error message about corrupt files, folder errors, or incorrect password when I try to unzip the database I purchased?
  
  During the unzip process, error messages about corrupted files, folder errors, or incorrect passwords are typically caused by attempting to unzip the database using the built-in zip utilities that come with Windows® or Mac operating systems. You must use a third-party zip utility to unzip the files, because the HCUP databases are compressed with a higher level of encryption than the standard utilities support. For additional information about third-party zip utilities, see Do I need special software to unzip the databases I purchased?
  
  If you are using a third-party zip utility and still receive a password error, refer to Where do I find the passwords for databases I purchased?



• Do I need special software to unzip the databases I purchased?
  
  Yes. HCUP databases use a process that compresses and encrypts the files into a password-protected zip file that only can be unzipped using a third-party zip utility such as ZIP Reader, SecureZIP®, or WinZip™. Attempts to unzip files using the built-in zip utilities in Windows® (Windows Explorer) or Mac (Archive Utility) will produce an error message warning of incorrect password and/or corrupted file or folder errors.
  
  Third-party zip utilities are available from the following reputable vendors on their official websites.
  
  
  • ZIP Reader (Windows) (free download offered by PKWARE®, Inc.)
  • SecureZIP for Mac (free evaluation and licensed/fee software offered by PKWARE, Inc.)
  • WinZip (Windows) (evaluation and fee versions offered by the WinZip corporation)
  • Stuffit Expander® (Mac) (free evaluation and licensed/fee software offered by Smith Micro corporation)
  • 7-Zip (Windows) (free download offered by the 7-Zip organization)



• Where do I find the passwords for databases I purchased?
  
  When your order for HCUP nationwide databases is activated for download, or your HCUP State database products are shipped, you will receive follow-up emails from the HCUP Central Distributor (Do-Not-Reply-HCUPDistributor@s-3.com) containing your order invoice, order status updates, and all necessary instructions for order fulfillment.
  
  A separate email contains the passwords for unzipping all database products in the order. The passwords are shown in a numbered list. You must compare that list to the list of databases and files in your order invoice; the password list uses the same sequence as the list of databases in the order.
  
  
  • The order invoice is embedded in each order status update email you received; it can also be printed from the Order Details in the online HCUP Central Distributor.
  • The Order Details screen also lists the databases in sequence. In the online HCUP Central Distributor, view the Orders tab under My Account.
  
  In the list of databases, an asterisk follows the database name if there is a corresponding password. Files that do not need a password (e.g., supplemental CCR files) do not have an asterisk.

• I did not purchase data but will be collaborating on a project with the data purchaser or otherwise will have access to HCUP data. Do I need to submit a Data Use Agreement?
  
  Everyone with access to HCUP data must take the online HCUP Data Use Agreement (DUA) Training and submit proof of training with the appropriate DUA(s) before gaining access to the data. If you are not the original data purchaser or data custodian, your DUA should be associated with the individual whose data you may access. The following options for submitting DUAs are detailed on the Data Use Info & Agreements tab in the online HCUP Central Distributor:
  
  
  • DUAs can be electronically acknowledged and submitted through the online HCUP Central Distributor by data users with proof of DUA training. A copy of the executed DUA will be available under My Account.
  • If you will be working on a specific project, ask your data custodian (the person whose data you will access) to issue you an electronic invitation to submit the DUAs through the online HCUP Central Distributor. Using the invitation will streamline the online DUA submission process and ensure that your DUAs are associated with the correct data custodian.
  • If you cannot access the online HCUP Central Distributor, proof of training and signed DUAs may be submitted by fax or postal service.

• What are the HCUP software tools?
  
  The HCUP software tools can be applied to HCUP and other administrative databases to systematically create new data elements from existing data, thereby enhancing a researcher's ability to conduct analyses. The HCUP software tools are available for download from the HCUP-US website and are free of charge.



• How often are the HCUP software tools updated? The HCUP software tools are updated annually to coincide with either fiscal year updates to the ICD-10-CM/PCS coding system or calendar year updates for CPT and HCPCS Level II codes. For this reason, it is always advisable to use the most recent version of the tool.
  
  The HCUP software tools for ICD-9-CM are no longer updated. These tools should be used only for administrative data before October 2015.



• What is the Clinical Classifications Software Refined (CCSR) for ICD-10-CM/PCS?
  
  The CCSR is a diagnosis and procedure categorization scheme that was developed by AHRQ. It aggregates ICD-10-CM/PCS diagnosis and procedures codes into clinically meaningful categories.
  
  
  • The CCSR for ICD-10-CM diagnoses groups diagnosis codes into more than 530 clinical categories. It balances the retention of the clinical concepts included in the CCS categories under ICD-9-CM and the specificity of ICD-10-CM diagnoses by creating new clinical categories. The CCSR for ICD-10-CM diagnoses is intended to be used analytically to examine patterns of healthcare in terms of cost, utilization, and outcomes; rank utilization by diagnoses; and risk-adjust by clinical condition.
  • The CCSR for ICD-10-PCS procedures groups procedure codes into more than 320 clinical categories. It capitalizes on the taxonomy and specificity of the ICD-10-PCS coding scheme and, where possible, retains the same surgical concepts from prior CCS versions. The CCSR for ICD-10-PCS procedures is intended to be used analytically to examine patterns of healthcare in terms of cost, utilization, and outcomes, in addition to ranking utilization by procedures.
  
  The CCSR replaces the beta version of the CCS for ICD-10-CM/PCS. The beta version of the CCS of ICD-10-CM/PCS codes will not be updated for newer codes (ICD-10-CM codes after October 2019 and ICD-10-PCS codes after October 2020).



• What are the major differences between the CCSR for ICD-10-CM diagnoses, the beta versions of the CCS for ICD-10-CM, and the CCS for ICD-9-CM?
  
  There are several key differences to note across the ICD-based diagnosis classification software: the CCSR for ICD-10-CM diagnoses, the beta versions of the CCS for ICD-10-CM diagnoses, and the CCS for ICD-9-CM diagnoses.

• What are the major differences between the CCSR for ICD-10-PCS procedures, the beta versions of the CCS for ICD-10-PCS, and the CCS for ICD-9-CM?
  
  There are several key differences to note across the HCUP ICD-based procedure classification software: the CCSR for ICD-10-PCS, the beta versions of the CCS for ICD-10-PCS, and the CCS for ICD-9-CM procedures.

• What is the Elixhauser Comorbidity Software Refined for ICD-10-CM?
  
  The Elixhauser Comorbidity Software Refined for ICD-10-CM is a product developed by AHRQ that identifies different pre-existing conditions based on secondary diagnoses (i.e., comorbidities) listed on hospital administrative data. This tool creates 38 variables that identify comorbidities (e.g., congestive heart failure, HIV) in hospital discharge records. In health services research, it is often important to control for comorbidities that are not directly related to the reason for the inpatient stay or outpatient encounter because they can impact resource allocation (e.g., length of stay or charges), as well as possibly affect outcomes used to assess the quality of care, such as in-hospital mortality.
  
  The Elixhauser Comorbidity Software was originally developed using ICD-9-CM diagnosis codes. The software was translated into ICD-10-CM prior to the availability of ICD-10-CM-coded data and released as a beta version. Once ICD-10-CM-coded data became available, the beta version of the Elixhauser Comorbidity Software was evaluated by clinical experts. The recommended modifications (implemented in v2021.1) transition the software tool out of its beta status and into the Elixhauser Comorbidity Software Refined for ICD-10-CM.



• What are the major differences between the Elixhauser Comorbidity Software Refined for ICD-10-CM, the beta versions of the Elixhauser Comorbidity Software for ICD-10-CM, and the Elixhauser Comorbidity Software ICD-9-CM?
  
  The Elixhauser Comorbidity Software Refined for ICD-10-CM retains the same clinical intent of defining a comprehensive list of comorbidity measures for use with large administrative databases; however, refinements were made to the clinical criteria used for identification of comorbidities and also with some of the comorbidity measures themselves. The number of comorbidity measures increases from 29 to 38 in v2021.1 with 3 measures added, 5 measures modified to create 12 more specific measures, and 1 measure discontinued. A subset of the comorbidity measures uses the present on admission (POA) indicators to determine whether the condition indicated by the secondary diagnosis arose prior to or during the hospital stay. The remaining comorbidity measures do not use POA indicators because the condition can be assumed to be pre-existing and not the result of hospital care (e.g., diabetes, AIDS).



• What is the Chronic Condition Indicator (CCI) for ICD-10-CM?
  
  The CCI for ICD-10-CM is a tool developed by the AHRQ that facilitates health services research by allowing the researcher to readily identify a diagnosis as indicating a chronic condition. Prior to v2021.1 (beta version), the CCI distinguished chronic from nonchronic conditions. Starting in v2021.1 (beta version), the CCI tool was expanded to identify four types of conditions:
  
  
  • Chronic: Examples include malignant cancer, diabetes, obesity, hypertension, and many mental health conditions
  • Acute: Examples include aortic embolism, bacterial infection, pregnancy, and an initial encounter for an injury
  • Both: Examples include persistent asthma with (acute) exacerbation, acute on chronic heart failure, and kidney transplant rejection
  • Not applicable (code cannot be used to identify a chronic or acute condition): Examples include external cause of morbidity codes, injury sequela codes, and codes starting with the letter Z for screening or observation.
  
  In 2021, AHRQ expects to conduct additional empirical analyses of the beta version of the tool and transition it out of beta status.



• What are the Procedure Classes for ICD-10-PCS?
  
  The Procedure Classes for ICD-10-PCS (beta version) facilitates health services research by allowing the researcher to readily determine (1) whether a procedure is diagnostic or therapeutic and (2) whether a procedure is expected to be performed in an operating room. The Procedure Classes for ICD-10-PCS (beta version) assign all ICD-10-PCS procedure codes to one of four categories:
  
  
  • Minor Diagnostic: Nonoperating room procedures that are diagnostic (e.g., B244ZZZ, Ultrasonography of Right Heart)
  • Minor Therapeutic: Nonoperating room procedures that are therapeutic (e.g., 02HQ33Z, Insertion of Infusion Device into Right Pulmonary Artery, Percutaneous Approach)
  • Major Diagnostic: Procedures that are considered operating room procedures that are performed for diagnostic reasons (e.g., 02BV0ZX, Excision of Superior Vena Cava, Open Approach, Diagnostic)
  • Major Therapeutic: Procedures that are considered operating room procedures that are performed for therapeutic reasons (e.g., 0210093, Bypass Coronary Artery, One Site from Coronary Artery with Autologous Venous Tissue, Open Approach).
  
  In 2021, AHRQ expects to conduct additional empirical analyses of the beta version of the tool and transition it out of beta status.



• What are the Utilization Flags for ICD-10-PCS?
  
  The Utilization Flags for ICD-10-PCS creates 30 data elements (i.e., utilization flags) that reveal additional information about use of healthcare services. By combining information from Uniform Billing (UB-04) revenue center codes and ICD-10-PCS procedure codes, it is possible to obtain a more complete picture of utilization of services rendered in healthcare settings such as hospitals, emergency departments, and ambulatory surgery centers.
  
  In 2021, AHRQ expects to conduct additional empirical analyses of the beta version of the tool and transition it out of beta status.



• What is the Clinical Classifications Software (CCS) for Services and Procedures?
  
  The CCS for Services and Procedures provides a method for classifying CPT and HCPCS Level II codes into more than 240 clinically meaningful procedure categories. The procedure categories are similar to the Clinical Classifications Software (CCS) for ICD-9-CM procedure classification with the addition of specific categories unique to the professional service and supply codes in CPT and HCPCS Level II codes.



• What is the Surgery Flags Software for Services and Procedures?
  
  The Surgery Flags Software for Services and Procedures identifies a subset of CPT codes as surgical procedures:
  
  
  • CPT Category I, Surgery:10004–69990
  • CPT Category I, Radiology procedures (added in v2019.2): 70010–79999
  • CPT Category I, Medicine services and procedures (added in v2019.2): 90281–99756, excluding the evaluation and management codes in the range 99201–99499
  • CPT Category III Codes, Temporary codes for emerging or experimental services, technology, or procedures (added v2018): 0042T–0593T
  
  Excluded are all other ranges of CPT Category I codes (i.e., codes specific to anesthesia, pathology and laboratory procedures, evaluation and management services, laboratory analyses, multianalyte assay), any CPT Category II codes, and all HCPCS Level II codes.
  
  CPT codes in the specified ranges are classified as one of three categories:
  
  
  • A narrowly defined surgery (Narrow) that is usually a major therapeutic procedure
  • A more broadly defined surgery (Broad) that includes major diagnostic and invasive minor therapeutic procedures
  • Neither a narrowly nor broadly defined surgery (Neither)



• What are the HCUP software tools for ICD-9-CM?
  
  The HCUP software tools for ICD-9-CM include the following:
  
  
  • Clinical Classifications Software (CCS) for ICD-9-CM
    Groups diagnosis and procedure codes into clinically meaningful categories
  • Chronic Condition Indicator (CCI) for ICD-9-CM
    Identifies diagnoses as chronic conditions
  • Elixhauser Comorbidity Software for ICD-9-CM
    Identifies secondary diagnoses as comorbidities
  • Utilization Flags for ICD-9-CM
    Identifies specific hospital services based on procedures and revenue center codes
  • Procedure Classes for ICD-9-CM
    Identifies major, minor, diagnostic, and therapeutic procedures
  • Surgery Flags for ICD-9-CM
    Identifies codes as narrowly defined therapeutic invasive surgeries or more broadly defined surgeries that include diagnostic invasive procedures

• What are the HCUP Supplemental Files?
  
  The HCUP Supplemental Files are available for use with the HCUP databases to enhance a researcher's ability to conduct analyses. These files are not applicable to other administrative databases. Most of these files are available for download from the HCUP-US website. Others may be ordered through the online HCUP Central Distributor. All are available free of charge.



• What are the American Hospital Association (AHA) Linkage Files?
  
  The HCUP AHA Linkage Files are used to supplement the HCUP SID, SASD, and SEDD with hospital-level information from the AHA Annual Survey Databases. This allows for richer empirical analysis especially where hospital characteristics may be important factors. The HCUP AHA Linkage Files include the hospital identifier used on the AHA Annual Survey Databases and the HCUP hospital identifier for those HCUP Partner States that release hospital identifiers.
  
  The HCUP AHA Linkage Files are available for download from HCUP-US for the HCUP Central Distributor SID, SASD, and SEDD beginning with 2006 data. The AHA Linkage Files are updated annually. The HCUP AHA Linkage Files prior to 2006 were included on the data CD-ROMs provided with purchase. Please note that not all HCUP Partner States release hospital identifiers.



• What are the Cost-to-Charge Ratio Files (CCR Files)?
  
  The CCR Files are linkable files developed by AHRQ that enable the conversion of total charges—defined as the amount a hospital billed for services—into how much the hospital services actually cost. Cost information was obtained from the hospital accounting reports in the Healthcare Cost Report Information System (HCRIS) files collected by the Centers for Medicare & Medicaid Services (CMS). Some imputations for missing values were necessary.
  
  Each CCR File contains hospital-specific cost-to-charge ratios based on all-payer inpatient cost for nearly every hospital in the corresponding SID, NIS, KID, and NRD. The CCR Files are updated annually for the SID, NIS, and NRD and every 3 years for the KID.
  
  AHRQ recently developed CCR Files for use with HCUP emergency department databases. Beginning with 2016 data, Emergency Department CCR Files will be available that contain cost ratios for nearly every hospital in the SEDD and NEDS.



• What are the Supplemental Variables for Revisit Analyses?
  
  The HCUP Supplemental Variables for Revisit Analyses, or revisit variables, are additional variables that were developed by AHRQ. They facilitate analyses to track patients across time and hospital settings exclusively in the SID, SASD, and SEDD while adhering to strict privacy guidelines.
  
  Beginning with 2009 data, the Revisit Variables are included in the Core file of the SID, SASD, and SEDD databases for select States that are purchased through the HCUP Central Distributor. For 2003–2008 data, the Revisit Variables are provided free of charge as a separate file with the applicable state databases.

• What is HCUPnet?
  
  HCUPnet is a free, online query system that provides statistics and data tables based on HCUP data. Its easy, step-by-step process allows users to explore many healthcare topics relating to hospital inpatient services, emergency department, and ambulatory settings. Users also may generate tables and graphs on national, regional, and county-level statistics including hospital readmissions and trends on hospital, emergency department, and ambulatory surgery use in the United States. In addition, State-specific statistics are available for States that have agreed to participate in HCUPnet.
  
  HCUPnet can access statistics from all HCUP databases: the NIS, the KID, the NRD, the NEDS, the NASS, selected SID, selected SASD, and selected SEDD.


Information provided by HCUPnet includes:


• Primary and secondary diagnoses and procedures
• Patient demographic characteristics
• Hospital characteristics
• Expected payer
• Total charges
• Discharge status
• Length of stay

Details are provided for conditions, procedures, diagnosis-related groups (MS-DRGs), external cause of injury codes, and major diagnostic categories (MDCs) by patient characteristics (age, sex, payer, community-level income, and urban/rural location), hospital characteristics (ownership, bedsize, teaching status, and rural/urban location), and region of the country. Statistics can be found for all discharges, for operating room procedures only, or for discharges that do not include maternal and newborn discharges.

Additional information provided by HCUPnet includes the following:


• In-hospital mortality for diagnoses and procedures
• Trends in inpatient and outpatient access, charges, and outcomes
• Utilization by special populations
• Most common conditions and procedures
• Variations in medical practice
• Charges for specific conditions
• Quality of care and patient safety
• Differences in outcomes between hospital type
• National estimates of hospital readmissions
• National benchmarks for the AHRQ Quality Indicators™
• Online z-test calculator to test statistical significance of differences between two weighted counts, means, or percentages


• How is HCUPnet different from the full HCUP databases?
  
  HCUPnet produces output by accessing precalculated statistics, tables and graphs of HCUP data to produce quick results. For this reason, and to protect patient confidentiality, not all types of queries are possible using HCUPnet. The full HCUP databases are purchased through the HCUP Central Distributor and require a statistical software package (such as SAS, SPSS, or Stata) for use. Researchers can program the software to extract the type of information they are seeking from the databases.
  
  HCUP Partners decide whether to release their State-level, public-release data through the HCUP Central Distributor and whether to have State-level statistics on HCUPnet. As a result, data from any given State may be available through one or both sources, and the years of participation can vary. Please review HCUPnet for a list of participating States and years of participation. For the Central Distributor, a summary table shows State participation by database and year. Complete database availability and pricing information is provided in the Database Catalog, which is found by navigating to the online HCUP Central Distributor.
  
  Additionally, national statistics are not available for all NIS years on HCUPnet.



• Is the national data on HCUPnet weighted?
  
  Yes. Unlike the full HCUP databases that are purchased through the HCUP Central Distributor, HCUPnet statistics have had the weighting applied. The data from HCUPnet are national estimates.



• How often is HCUPnet updated?
  
  HCUPnet is updated as databases are released. The national statistics are updated annually, and State statistics are updated as new State data are processed. Available States and years are listed on the HCUPnet pathways.



• HCUPnet provides national readmission statistics. Is this information available in a full nationwide database?
  
  Yes. Statistics on national readmission rates are available on HCUPnet or through the NRD. The NRD can be purchased through the HCUP Central Distributor.



• How does HCUPnet work?
  
  HCUPnet is based on aggregate statistics tables to speed up data transfer and protect individual records, so not all possible queries can be addressed. HCUPnet is designed to walk the user through each step of building a query.

• What articles and reports are available on the HCUP-US website?
  
  HCUP produces a number of publication series featuring HCUP data and tools. These publications and reports provide people with ready-made sources of statistics and guidance on a range of healthcare related subjects. Examples include the following:
  
  
  • HCUP Statistical Briefs, which present simple, descriptive reports on a variety of specific, healthcare related issues
  • HCUP Methods Series Reports, which feature a broad array of methodological information on the HCUP databases and software tools
  • HCUP Topical Reports, which provide information on various priority populations
  • HCUP Infographics, which provide a visual representation of HCUP Statistical Briefs and other data
  • HCUP Findings-At-A-Glance provides snapshots covering a broad range of health policy issues related to hospital use and costs.
  
  Additionally, the HCUP-US website has an HCUP Publications Search feature, which allows visitors to search keywords for peer-reviewed articles and AHRQ reports that used HCUP data or products to support their research. The HCUP-US website showcases high-quality examples of articles in its Research Spotlights feature.

• What is the HCUP Online Tutorial Series?
  
  The HCUP Online Tutorial Series is a set of free, interactive courses designed to provide data users with information about HCUP data and tools, as well as training on technical methods for conducting research with HCUP data.



• What topics are available?
  
  Topics in the Online Tutorial Series include the following:
  
  
  • HCUP Overview Course: provides information about HCUP data, software tools, and products.
  • Load and Check HCUP Data Tutorial: provides instructions on how to unzip (decompress) HCUP data, save it on the computer, and load the data into a standard statistical software package.
  • Calculating Standard Errors Tutorial: shows users how to accurately determine the precision of the estimates produced from the HCUP nationwide databases.
  • Nationwide Readmissions Database (NRD) Tutorial: introduces users to the design, data, and uses for this nationwide database.
  • HCUP Sample Design Tutorial: explains the sampling strategy of the National (Nationwide) Inpatient Sample (NIS), Kids' Inpatient Database (KID), and Nationwide Emergency Department Sample (NEDS) nationwide databases.
  • Producing National HCUP Estimates Tutorial: demonstrates how the NIS, KID, and NEDS nationwide databases can be used to produce national and regional estimates.
  • Multi-Year Analysis Tutorial: presents solutions that may be necessary when conducting analyses that span multiple years.
  • HCUP Tools for ICD-10-CM/PCS Loading Tutorial: provides instructions on how to unzip (decompress) the beta versions of the HCUP Tools for ICD-10-CM/PCS, save them onto the computer, and load them into a standard statistical software package for application to HCUP or other administrative databases. Users will also learn how to verify that the tool has loaded correctly.

• Tracking Readmissions Using the NRD
• Using HCUP to Study Emergency Department Visits
• Running Queries in HCUPnet

• What types of questions can HCUP User Support answer?
  
  HCUP User Support can help (1) find, select, and access the appropriate HCUP databases, tools, and documentation; (2) navigate and use the HCUP-US and HCUPnet websites; (3) troubleshoot issues with HCUP tools; (4) investigate possible data or documentation errors; (5) support in the interpretation of your HCUP data output; and (6) guide you in the appropriate use and reporting of HCUP data.
  
  If you have questions concerning current HCUP database orders and invoices, downloading HCUP nationwide databases, unzipping HCUP State or nationwide database products, or submitting required HCUP DUAs, training certificate codes, or data re-use requests, please contact the HCUP Central Distributor.



• Are there types of questions that HCUP User Support cannot answer?
  
  HCUP User Support cannot answer questions related to programming software services or support, data coding, complex analyses, research design, or running, revising, or customizing HCUP tools. Staff may be able to guide you to other resources that are specific to your needs.



• Can HCUP User Support assist with my study design and methodology?
  
  HCUP User Support cannot assist with HCUP research designs. However, many users have found HCUP's Publications Search page helpful in learning how other researchers have constructed their methodology.



• Are there requirements for publishing with HCUP data?
  
  Yes. Before publishing with HCUP data, HCUP User Support recommends reviewing the Requirements for Publishing With HCUP Data page.