ResDAC has developed over 100 articles that cover topics ranging from the CMS data request process through using the data for a study. CMS has developed additional resources, including TAF data quality briefs and TAF data quality state snapshots, examining the quality of the Medicaid data.
CMS offers files from aggregate data to individual person level data. This article describes the differences between the aggregate, public use files, the limited data sets,…
This article describes the Federal Regulations that govern the release of CMS data for research.
The purpose of this article is to identify 1) common strengths of Medicare and Medicaid administrative data and 2)  broad limitations for researchers to consider when…
Researchers who are interested in studying Part D utilization within the Medicare Current Beneficiary Survey (MCBS) can do so by using the MCBS Cost and Use for years 2006 through 2013. This article provides an overview of where Part D utilization information located within the MCBS during these years, as well as the list of PDE variables included with the file.
This article describes the Federal Regulations that govern the release of CMS data for research.
CMS offers several claim-level files that contain outpatient claims; that is, facility claims submitted for care covered under Part B. Three versions of the LDS files are described:Outpatient file,Outpatient Prospective Payment System (OPPS) file, and OPPS Partial Hospitalization file.
To describe the CMS cell size suppression policy and provide examples of common scenarios and possible options.
Claims for ambulance services are found in both the Carrier and the Outpatient claims data. This article describes how to identify ambulance services.
Part D Event (PDE) files for data years prior to 2010 may include the values of “XX” or “NA” for any of the four Utilization Management variables. This article describes when and why each value was used.
CMS research files do not include beneficiary risk adjustment scores.  However, CMS does provide the programming code and instructions to calculate the three risk adjustments that CMS uses as the basis for managed care payment.
Cost report variables are split between two data files depending on the format of the variable. A master table lists all cost report variables and the format. The “Usage” column in the master table specifies the format of the variable, which determines the file location.
Beginning in 2008, some hospital provider numbers appearing in the claims contain a “V” in the fifth position of the six-digit Medicare Provider Number. Usually, the fifth position is a number, not a character. These hospital provider numbers appear in the MedPAR, Inpatient and Outpatient files for both RIF and LDS versions.  ResDAC recommends that researchers remove these claims.
CMS updated several Medicare cost report forms. As a result, during the year of the transition and up to one year after, the facility will have two separate data downloads, one that includes all the data collected under the old form and another one under the new form. 
The Medicare cost report files are created by Fiscal Year. The definition used to create the fiscal year files vary depending on the provider type.
When importing Medicare cost reports into Microsoft Access, data users should use the “link specifications” option to ensure that each variable imports with the correct data type.