Behind the Data: Medicare Provider Charge Data

Originally cross-posted from

The Centers for Medicare & Medicaid Services (CMS) have publicly released for the first time data sets showing hospitals charges and Medicare payments for the 100 most common Medicare inpatient stays and for 30 select Ambulatory Payment Classification Codes (APCs). partnered with the Robert Wood Johnson Foundation and Health 2.0 to task designers and programmers to visualize this data to create greater transparency in the healthcare field in our Visualizing Hospital Price Data challenge. We wanted to give the community additional context to inform their projects, so we’ve asked Niall Brennan, the Director of the Office of Information Products and Data Analytics at CMS, to explain the data and to speak on the importance of this release.



Visualizing: Describe the data sets. What information do they each contain? How many columns and rows are in each?

Niall Brennan: The Medicare Provider Charge data include information comparing the charges for the 100 most common inpatient services and 30 common outpatient services. The inpatient data include hospital-specific charges for the more than 3,000 U.S. hospitals that receive Medicare Inpatient Prospective Payment System (IPPS) payments for the top 100 most frequently billed discharges, paid under Medicare based on a rate per discharge using the Medicare Severity Diagnosis Related Group (MS-DRG) for Fiscal Year (FY) 2011. These DRGs represent almost 7 million discharges or 60 percent of total Medicare IPPS discharges. The outpatient data include estimated hospital-specific charges for 30 Ambulatory Payment Classification (APC) Groups paid under the Medicare Outpatient Prospective Payment System (OPPS) for Calendar Year (CY) 2011. The Medicare payment amount includes the APC payment amount, the beneficiary Part B coinsurance amount and the beneficiary deductible amount. The inpatient file includes 163,065 rows of data and 11 columns. The outpatient file contains 41,175 rows of data and 11 columns.

V: How do hospitals determine what they will charge for items and services provided to patients?

NB: Hospitals determine what they will charge for items and services provided to patients and these charges are the amount the hospital generally bills for an item or service. Hospitals typically develop “charge masters” which hold the prices for all services and products and these lists are usually adjusted annually based on the prior year’s prices. Often, hospitals will have different charge masters for different payors. CMS does not pay hospitals based on these charges, but instead payments are based on statutorily set fee schedules. Inpatient acute-care services are paid by Medicare based on a rate per discharge using the Medicare Severity Diagnosis Related Group (MS-DRG) to which the Medicare patient’s case is assigned. The MS-DRG is a classification system that groups similar clinical diagnoses and the procedures the hospital furnished to treat those conditions during the inpatient stay.

V: What are the specific advantages and difficulties unique to working with data of this scope?

NB: The advantages of these data include the ability to view specific provider’s average charge and payment data for a very detailed set of the most commonly utilized inpatient and outpatient services. For the first time, the general public has access to granular data on the hospital facilities that they may use and researchers and computer application developers have access to data that allows for regional area comparisons or development public friendly websites and tools to visualize this data. Additionally, CMS released this data in a variety of formats, including Microsoft Excel tables with filtering and sorting capabilities and in machine readable formats including comma separated value delimited files and through JSON application programming interfaces on While CMS attempted to make this data very easy to use by all parties, some possible difficulties using these data may be due to the vast size of the data files, which may be overwhelming to certain groups, including Medicare beneficiaries and the lay public in general. CMS is excited that the Robert Wood Johnson Foundation is hosting this challenge to increase the usability and visibility of this important data release.

V: This is one of the largest data releases from Medicare in a number of years, and it has garnered a lot of media attention and public interest. What do you hope results from this increased focus?

NB: CMS is committed to greater transparency in the health care system. We have already seen important impacts from the release of this data in terms of the broader conversation around the appropriateness of hospital charging practices and the massive variations in charges from hospital to hospital, even in the same city. We hope that this and future data releases promote a greater understanding of health care pricing, utilization and quality to enable consumers to make more informed decisions regarding their health care and their choices of health care providers.

V: Does CMS have any plans to release the metadata for this release? And how do you see CMS data being used in coming years?

NB: CMS included metadata column descriptions in the Microsoft Excel worksheets which accompany the data. Additionally, metadata entries were provided for the data linked by the website. CMS is hopeful that this and other data releases will spur a vibrant health data ecosystem that incorporates CMS and other data into the tools that patients, providers and other stakeholders need to provide better care at lower cost.

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