Skip Navigation Archive: U.S. Department of Health and Human Services U.S. Department of Health and Human Services
Archive: Agency for Healthcare Research Quality
Archival print banner

This information is for reference purposes only. It was current when produced and may now be outdated. Archive material is no longer maintained, and some links may not work. Persons with disabilities having difficulty accessing this information should contact us at: Let us know the nature of the problem, the Web address of what you want, and your contact information.

Please go to for current information.

Data Sources—Agency for Healthcare Research and Quality

2011 National Healthcare Quality and Disparities Reports

The National Healthcare Quality Report (NHQR) is a comprehensive national overview of quality of health care in the United States. It is organized around four dimensions of quality of care: effectiveness, patient safety, timeliness, and patient centeredness.

Healthcare Cost and Utilization Project (HCUP)


U.S. Department of Health and Human Services, Agency for Healthcare Research and Quality (AHRQ).


HCUP databases bring together the data collection efforts of State government data organizations, hospital associations, private data organizations, and the Federal Government to create a national information resource of discharge-level health care data.

HCUP includes a collection of longitudinal hospital care data, with all-payer, discharge-level information beginning in 1988. Four HCUP discharge datasets were used:

  1. The HCUP Statewide Inpatient Databases (SID) include discharges for all hospitals from 44 participating States. In aggregate, the SID represents almost 95% of all U.S. community hospital discharges.

    The SID contains a core set of clinical and nonclinical information on all patients, regardless of payer. In addition to the core set of uniform data elements common to all of the SID, some States report other data elements, such as patient race.

  2. The Nationwide Inpatient Sample (NIS) is a stratified sample of hospitals, drawn from the subset of hospitals in HCUP Partner States that can be matched to the American Hospital Association (AHA) survey data. Hospitals are stratified by region, location/teaching status (within region), bed size category (within region and location/teaching status), and ownership (within region, location/teaching status, and bed size categories). Weights are used to develop national estimates. More than 8 million discharges from more than 1,000 hospitals in 40 States are represented in the NIS, approximating a 20% stratified sample of U.S. community hospitals.

  3. The Nationwide Emergency Department Sample (NEDS) was constructed using the HCUP State Emergency Department Databases (SEDD) and the SID. The SEDD captures discharge information on emergency department (ED) visits that do not result in an admission (i.e., treat-and-release visits and transfers to another hospital). The SID contains information on patients initially seen in the ED and then admitted to the same hospital.

  4. The NEDS is a stratified sample of 20% of U.S. hospital-based ED events drawn from the States providing ED data to HCUP. Twenty-nine HCUP Partner States participated in the 2009 NEDS: AZ, CA, CT, FL, GA, HI, IA, IL, IN, KS, KY,MA, MD, ME, MN, MO, NC, NE, NH, NJ, NY, OH, RI, SC, SD, TN, UT, VT, and WI.

  5. The SID disparities analysis file was created from SID data to provide national estimates for the National Healthcare Disparities Report. It consists of weighted records from a sample of hospitals from 26 States participating in HCUP that have high-quality race/ethnicity data: AR, AZ, CA, CO, CT, FL, GA, HI, KS, MA, MD, MI, MO, NH, NJ, NY, OK, RI, SC, TN, TX, UT, VA, VT, WI, and WY in 2007. These 26 States accounted for 63% of U.S. hospital discharges (based on the AHA annual survey).

  6. The HCUP databases combine racial/ethnic categories, resulting in the following subgroups: Hispanic of all races, and non-Hispanic Blacks, Asians and Pacific Islanders, and Whites. Not all States uniformly collect race and ethnicity data; when a State and its hospitals collect Hispanic ethnicity separately from race, HCUP uses Hispanic ethnicity to override any other racial category.

Community hospitals from the 26 States were sampled to approximate a 40% stratified sample of U.S. community hospitals, with stratification based on five hospital characteristics: geographic region, hospital ownership, urbanized location, teaching status, and bed size. Hospitals were excluded from the sampling frame if the coding of patient race was suspect. Once the 40% sample was drawn, discharge-level weights were developed to produce national-level estimates when applied to the SID disparities analysis file. The final SID disparities file included about 15 million hospital discharges from almost 1,900 hospitals.

Primary Content

The HCUP NIS and SID contain more than 100 clinical and nonclinical data variables, including age, gender, race, ethnicity, length of stay, discharge status, source of payment, total charges, hospital size, ownership, region, teaching status, diagnoses, and procedures.

The NHQR and NHDR measures that use HCUP data are based on AHRQ Quality Indicators (QIs), a set of algorithms that may be applied to hospital administrative data to quantify quality issues among inpatient populations. The QIs fall into four categories:

  1. Inpatient Quality Indicators (IQIs) reflect quality of care in hospitals and currently include 15 mortality indicators for conditions or procedures. The IQIs include 11 procedures for which utilization varies across hospitals or geographic areas and 6 procedures for which outcomes may be related to the volume of procedures.
  2. Prevention Quality Indicators (PQIs) assess hospital admissions for 14 ambulatory care-sensitive conditions that evidence suggests may be avoided, in part, through high-quality ambulatory care.
  3. Patient Safety Indicators (PSIs) reflect potential inpatient complications and other patient safety concerns following surgeries, other procedures, and childbirth. The most recent version of the PSI software has 27 measures.
  4. Pediatric Quality Indicators (PDIs) examine 18 conditions that pediatric patients experience within the health care system that may be preventable by changes at the system or provider level. In earlier versions of the QI software, some PDI measures were part of the IQI, PSI, and PQI modules.

Population Targeted

The population targeted by HCUP databases includes any person, U.S. citizen or foreign, using non-Federal, nonrehabilitation, community hospitals in the United States as defined by AHA. AHA defines community hospitals as "all non-Federal, short-term, general, and other specialty hospitals, excluding hospital units of institutions" (Health Forum, 2010). Included among community hospitals are specialty hospitals, such as obstetrics-gynecology, ear-nose-throat, short-term rehabilitation, orthopedic, and pediatric institutions. Also included are public hospitals and academic medical centers. The NIS and analyses of the SID for the NHQR and NHDR excluded short-term rehabilitation hospitals (beginning with 1998 data), long-term hospitals, psychiatric hospitals, and alcoholism/chemical dependency treatment facilities.

Although not all States participate in the HCUP database, the NIS, the NEDS, and the SID disparities analysis files are weighted to give national estimates using weights based on all U.S. community, nonrehabilitation hospitals in the AHA Annual Survey Database (Health Forum, 2007).

Demographic Data

Age, gender, race, insurance coverage, median household income of the patient's ZIP Code, urbanized location, and region of the United States.

Years Collected

Since 1988.



Geographic Estimates

National; four U.S. Census Bureau regions; States (for States participating in SID that agree to the release).

Contact Information

Agency home page:

Data system home page:

AHRQ Quality Indicators:


Coffey R, Barrett M, Houchens R, et al. Methods applying AHRQ Quality Indicators to Healthcare Cost and Utilization Project (HCUP) data for the eighth (2010) National Healthcare Quality Report and National Healthcare Disparities Report. HCUP Methods Series Report #2010-06. Rockville, MD: Agency for Healthcare Research and Quality; November 2010. Available at:

For detailed information about QI measures, refer to the individual guides to the Quality Indicators listed below, available from the archives at

  • Guide to Inpatient Quality Indicators: quality of care in hospitals—volume, mortality, and utilization. Version 3.1. Rockville, MD: Agency for Healthcare Research and Quality; 2007.
  • Guide to Patient Safety Indicators. Version 3.1. Rockville, MD: Agency for Healthcare Research and Quality; 2007.
  • Guide to Prevention Quality Indicators: hospital admission for ambulatory care sensitive conditions. Version 3.1. Rockville, MD: Agency for Healthcare Research and Quality; 2007.
  • Measures of pediatric health care quality based on hospital administrative data: the Pediatric Quality Indicators. Rockville, MD: Agency for Healthcare Research and Quality; 2006.

Sources of HCUP Data

  1. Arizona Department of Health Services.
  2. Arkansas Department of Health.
  3. California Office of Statewide Health Planning and Development.
  4. Colorado Hospital Association.
  5. Connecticut Hospital Association.
  6. Florida Agency for Health Care Administration.
  7. Georgia Hospital Association.
  8. Hawaii Health Information Corporation.
  9. Illinois Department of Public Health.
  10. Indiana Hospital Association.
  11. Iowa Hospital Association.
  12. Kansas Hospital Association.
  13. Kentucky Cabinet for Health and Family Services.
  14. Louisiana Department of Health and Hospitals.
  15. Maine Health Data Organization.
  16. Maryland Health Services Cost Review Commission.
  17. Massachusetts Division of Health Care Finance and Policy.
  18. Michigan Health and Hospital Association.
  19. Minnesota Hospital Association.
  20. Missouri Hospital Industry Data Institute.
  21. MHA—An Association of Montana Health Care Providers.
  22. Nebraska Hospital Association.
  23. Nevada Department of Health and Human Services.
  24. New Hampshire Department of Health and Human Services.
  25. New Jersey Department of Health and Senior Services.
  26. New Mexico Health Policy Commission.
  27. New York State Department of Health.
  28. North Carolina Department of Health and Human Services.
  29. Ohio Hospital Association.
  30. Oklahoma State Department of Health.
  31. Oregon Association of Hospitals and Health Systems.
  32. Pennsylvania Health Care Cost Containment Council.
  33. Rhode Island Department of Health.
  34. South Carolina State Budget and Control Board.
  35. South Dakota Association of Healthcare Organizations.
  36. Tennessee Hospital Association.
  37. Texas Department of State Health Services.
  38. Utah Department of Health.
  39. Vermont Association of Hospitals and Health Systems.
  40. Virginia Health Information.
  41. Washington State Department of Health.
  42. West Virginia Health Care Authority.
  43. Wisconsin Department of Health Services.
  44. Wyoming Hospital Association.

National CAHPS® Benchmarking Database (NCBD)


U.S. Department of Health and Human Services, Agency for Healthcare Research and Quality (AHRQ) in association with a consortium of public and private organizations.


By responding to a standardized set of questions administered through a mail or telephone questionnaire, health plan members report on their experiences and rate their health plans and providers in several areas. Participation in the CAHPS® (Consumer Assessment of Healthcare Providers and Systems) database is voluntary.

Medicare managed care data were obtained from the Centers for Medicare & Medicaid Services (CMS) for survey participants. The 4.0 and 3.0 Medicaid data were obtained from data submitted directly to the CAHPS Database by State Medicaid agencies and individual health plans. The 4.0 and 3.0 Commercial sector data were obtained from the National Committee for Quality Assurance (NCQA), under an agreement between the CAHPS Database and NCQA.

Survey Sample Design

CAHPS surveys are administered to a random sample of health plan members by independent survey vendors, following standardized procedures. Since 1998, health plans, purchaser groups, State organizations, and others have participated in this component.

The CAHPS sampling recommendation is to achieve a minimum of 300 completed responses per plan, with a 50% response rate. The plan samples are not adjusted for unequal probabilities of selection. This logic stems from the principle that the precision of the estimates depends primarily on the size of the sample and not on the size of the population from which it is drawn. Therefore, the given sample size will give the same precision for means or rates regardless of the overall size of the population.

Primary Survey Content

The questions in the 4.0 version of the CAHPS Adult and Child Health Plan Surveys fall into four major "composites" that summarize consumer experiences in the following areas: getting needed care, getting care quickly, how well doctors communicate, and health plan information and customer service.

Population Targeted

CAHPS has specific populations for specific surveys and databases, such as adults, children, children with chronic conditions, and participants in commercial, Medicaid, Medicare, or Medicare managed care plans. See specific tables and measure specifications for more information.

Estimates for tables based on CAHPS data were calculated using plan-level weights; i.e., all respondents in a plan received the same weight. Further, all plans within a State were weighted to contribute equally to the State-level statistic.

Demographic Data

Age, gender, education, race, ethnicity, region.

Years Collected

Since 1998.



Geographic Estimates

State; four U.S. Census Bureau regions.

Contact Information

Agency home page:

Data system home page:


National CAHPS Benchmarking Database. 2008 CAHPS Health Plan Survey chartbook: what consumers say about their experiences with their health plans and medical care. Rockville, MD: Agency for Healthcare Research and Quality; October 2008.

Return to Contents
Proceed to Next Section

Page last reviewed October 2014
Internet Citation: Data Sources—Agency for Healthcare Research and Quality: 2011 National Healthcare Quality and Disparities Reports. October 2014. Agency for Healthcare Research and Quality, Rockville, MD.


The information on this page is archived and provided for reference purposes only.


AHRQ Advancing Excellence in Health Care