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 It was current when produced and may now be outdated. Archive material is no longer maintained, and some links may not work.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.

HCUP: Questions and Answers

Questions and Answers

Questions asked by participants during the 2010 webinar describing the Healthcare Cost and Utilization Project (HCUP).

A Web conference entitled Healthcare Cost and Utilization Project (HCUP): Overview of HCUP Databases, Tools, and Resources was held on May 18, 2010. These are the questions asked by participants during the event, with the associated answers.

Question: What is the difference between charges and costs?

Answer: Hospital charges are actually the amount that the hospital charges for the entire hospital stay. It's important to remember when using HCUP data that the charge isn't specific to a procedure or a condition but to the entire hospital stay. The charges are the amount that the hospital charged for the entire hospital stay, whereas costs tend to reflect the actual cost of production. Total charges can be converted to cost using the cost-to-charge ratio file that I mentioned earlier. In general, costs are less than charges. For each hospital, a hospital-wide cost-to-charge ratio can be used to determine costs.

Question: Since you mentioned the cost-to-charge ratio files, are they adjusted for cost of living in the various regions?

Answer: In a way they are. The cost-to-charge ratio files are hospital-specific files that take into account the hospital's location. So cost of living is indirectly taken into account based on where the hospital is located. There's no need to further adjust for that.

Question: Can HCUP be used to look at readmissions, and if so, what would be involved in the analysis?

Answer: The revisit analyses files allow HCUP researchers to link together the State Inpatient Databases (SID), the State Ambulatory Surgery Databases (SASD), and the State Emergency Department Databases (SEDD) in order to identify sequential visits for an individual. You can also use the available clinical information to determine if the visits are unrelated and expect followup, complications from a previous treatment, or an unexpected revisit or hospitalization.

There is a recent example that was published in the Journal of the American Medical Association (JAMA) looking at readmissions for sickle cell disease in the emergency department and hospitalization from selected States in 2005 and 2006 SID and SEDD. That study found that among patients with sickle cell disease, acute care encounters and rehospitalizations were frequent, particularly for 18- to 30-year-olds and people who were publicly insured. So the revisit files are a great tool to look at readmission. It's simply a matter of linking together the relevant databases or data years for those States that release that information.

Question: Has the Agency for Healthcare Research and Quality (AHRQ) received feedback from either hospital associations or the hospitals themselves about being competitively at a disadvantage because physicians or ambulatory surgical centers would be able to access information that typically most other businesses wouldn't have access to in other industries? How does AHRQ go about addressing that? Is there any literature to support agencies who wish to make that information more available for public consumption, that there is no harm in making it available?

Answer: It brings up a good point, which is that the data that the project produces are intended for research and policy purposes. However, everyone who uses the data needs to sign a data use agreement in which they agree not to identify physicians, individuals, patients, or hospitals. To that end, the data is not intended or allowed to be used to identify and separate out individual hospitals.

Question: My first question I heard throughout the presentation various mentions of free tools in addition to tools where cost is not mentioned. Could you review what is free and what is not on HCUP and what is the cost to access the tools?

Answer: HCUPnet is totally free. That can be used by anyone and you simply go online and access that. The databases vary in price. Those are available for purchase through the HCUP central distributor or the State databases can be purchased through the States themselves. You can find information about the exact costs of all of the databases on the HCUP user support website by clicking on the central distributor link. It will show you exactly what data years and States are available for purchase and how much it costs.

The database is available through the HCUP central distributor at the national level. Those prices are set by AHRQ. There is also a student fee, which is a reduced rate. The State-level databases really vary in how much they cost. It can range anywhere from 20 dollars up to 3,000 dollars. That's the cost for State-level databases, so there's some variability in the costs.

Question: Is there individual hospital data available, or is it only aggregated by State?

Answer: If you access information through HCUPnet, all of the information publicly available on HCUPnet is in aggregated form. You won't be able to identify any individual hospitals or discharges and they have taken precautions to suppress information that might potentially identify. That's why you saw stars in some of the boxes in the presentation.

When you purchase the full database, identifiable information is available. You won't have patient names or Social Security numbers or anything like that, but you will be able to identify hospitals and link to other files, such as the American Hospital Association (AHA) linkage files. But again, there is a data use agreement not to identify specific individuals, hospitals, patients, physicians, and so on.

Question: Is payment data available? You talked about charges and costs, but I didn't hear anything about payments.

Answer: We don't have information on payments. We have charge information from which we extrapolate costs and AHRQ is currently working on a price-to-charge ratio from which they would be able to extract the price for services. We don't have information on what was reimbursed to the hospitals.

Question: How often is the HCUP data refreshed?

Answer: We collect data from the States on an annual basis, so they provide a year's worth of data to us. Then typically there's about an 18-month lag between the end of the calendar year and the availability of HCUP data. Currently, we have 2008 State-level databases released, as you saw during our HCUPnet demo. We're currently working on the 2008 national database. There is about an 18-month lag between the end of the calendar year and the availability of HCUP data.

Question: What sort of quality checks are performed on HCUP data?

Answer: Most of the validation that we do for HCUP is looking at the completeness of specific data fields. While we do limited checks for accuracy, like gross checks to see whether males are being coded with giving birth or females are being coded with male-specific procedures, we don't do detailed checks on the accuracy of coding. We do compare the HCUP Nationwide Inpatient Sample (NIS) counts with other national data sources of hospital care, such as the National Hospital Discharge Survey files. Additional information about the quality checks can be found in methods reports on the HCUP Web site.

Question: Can I look at patient admissions rather than discharges?

Answer: The NIS record is created only after the patient is discharged from the hospital, so it's really more appropriate to use the NIS to look at care from the discharge perspective rather than from the admission perspective. It also brings up another great point, which is that these are not patients but these are discharges. This is discharge-level information. When you're looking at revisit analyses, you can consider looking at patient-level information, but each line in the file represents an individual discharge. It's not an admission and it's not a patient; it's a discharge.

Question: Are older annual databases updated to account for a claims lag?

Answer: I don't exactly understand the question, but I'll answer it the best I can. How it works is that we get all of the data from a State, so there's lag time involved in that. For instance, we don't ask a State to send us their data until they feel like they have complete data for a given data year. After they send it to us, we process and format it. We try to capture as much information as we can, but that's why there is an 18-month lag time between when the actual data calendar year ended and when the data becomes available.

Question: When will the NIS, Kids' Inpatient Database (KID), and Nationwide Emergency Department Sample (NEDS) be released?

Answer: There's typically about an 18-month lag time, so we're currently working on the 2008 NIS and we expect that that will be released later this summer. The KID and NEDS are also in the works. The KID is produced every 3 years, starting in 1997, so we've got '97, 2000, 2003, 2006, and 2009. The KID will probably be released in 2011. We're currently working on the NEDS and we expect that to be released later this year.

Question: We have purchased HCUP data in the past. Do we need to fill out the application every time we order a new HCUP yearly dataset?

Answer: Yes, a new application kit is needed each time a new dataset is purchased and a new data use agreement will also need to be signed. It's not necessary to take the HCUP data use agreement training course more than once. There's a data use agreement training course online. It takes about 15 minutes to complete. You complete that and then you receive a code, a completion code or a certificate code. Then you'll put that on your application when you first apply. After the first submission, you don't need to repeat the course, but you will need to submit a new form. Similarly, if you have a colleague or student who is going to be using the database that you've purchased, it's your responsibility to have that person also take the online data use agreement training course and submit a data use agreement.

Question: When will the MONAHRQ [My Own Network Powered by AHRQ] application be released?

Answer: This is something that we are very eager to get released. We know people are really excited about it. We are doing some final testing on it and hope to have it out pretty soon. I wish I could tell people an exact date, but we expect it to come out really soon. I promise that when it comes out, we will let all of you know.

Return to Contents

Page last reviewed August 2010
Internet Citation: HCUP: Questions and Answers: Questions and Answers. August 2010. 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