Knowledgebase

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.
Introductory
Articles
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…
The purpose of this article is to provide CMS’s definition of uncompensated care, the years collected, and location in the Medicare hospital cost report forms.
This article outlines the provider identification numbers that are available in the MAX files and options for linking to the Medicare Provider Number.
This article describes the structure of the Medicare cost reports and provides instructions for identifying specific data elements for specific facilities. While the examples and screenshots provided below are specific to the hospital cost reports, the discussion on file structure and logic used for identifying specific variables are applicable to any facility cost report. 
The purpose of this knowledge base article is to 1) present an overview of International Classification of Disease (ICD) codes and versions available, 2) describe where researchers can find these codes in the Medicare claims, and 3) understand how ICD codes appear in the data.
This article has three goals: (1) to describe missing patterns on pain variables; (2) to describe the difference between real missing and skip patterns; (3) to describe which assessments should be used for calculating pain measures. This information is most relevant for researchers who work on either creating their own pain measures or constructing CMS quality measures. The new MDS 3.0 requires nursing home staff to interview residents regarding health conditions, such as pain, mood and cognitive function through…
Providers that bill Medicare use codes for patient diagnoses and codes for care, equipment, and medications provided. This articles provides resources to identify the codes used in Medicare claims files.
The Internet Archive is a useful resource for finding historical copies of the Centers for Medicare and Medicaid Services (CMS) websites, reports or statistics that are no longer available.
Researchers and data users who are working with CMS files may need to map zip code information to CMS carriers and localities. This article describes where to find current and historical versions of the file.
This article provides instructions on how to open the Medicare Physician/Supplier Procedure Summary Master (PSPS) file in Microsoft Access or SAS.
The purpose of this article is to define a Long-Term Care Hospital (LTCH) and to identify the files that contain claims submitted by a LTCH.
Under changes to the Part 2 regulations on January 17, 2017, CMS is now permitted to include substance use disorder claims data in the Research Identifiable Files (RIFs).  Research Identifiable Files shipped or extracted in the VRDC after 05/22/2017 are no longer subject to the redaction.
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.