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…
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.
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 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 requesting and using the data.
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.
This article provides resources for obtaining statistics and reports related to the Medicare and Medicaid programs and their beneficiaries. The following Medicare/Medicaid statistical and summary data resources address some of the most common requests for this type of information. These are by no means exhaustive.
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.
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.
Detailed information about Medicare Part D drug plan formularies is available in two CMS data files. Important differences in the files are outlined below, including whether or not the files can be linked to other data sources.
The CMS National Plan and Provider Enumeration System (NPPES) provides basic information about all organization and individual providers with a National Provider Identifier (NPI).  This article provides a brief overview of how to access the NPPES and the information that it contains.
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.
This article outlines the provider identification numbers that are available in the MAX files and options for linking to the Medicare Provider Number.