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…
Availability of provider variables Provider variable completeness Provider variable definitions
This article presents the data options available to researchers studying the End-Stage Renal Disease (ESRD) population. 
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.
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.
Beneficiary death information is available in several of the Medicare enrollment files. Limited death information is also found in other files, such as the MedPAR. This article describes the variables found in each.
A number of CMS Limited Data Set (LDS) files are released first as a Proposed Rule file and then as a Final Rule file. This article provides a brief description of the differences between those two files.
This article provides resources for the assessment of the quantity and quality of managed care organization (MCO) encounter data in the Medicaid Analytic eXtract (MAX) files.
Researchers who request the Minimum Data Set (MDS) from CMS will need to determine whether they would like data based on Target Date or Submission Date. This article provides definitions for Target and Submission dates and examples for when each selection is useful.
The beneficiary eligibility and enrollment files have changed in content and name over the years. It is important to understand the timing of these changes and the unique features of each file if you are using older files or see them referenced in articles.
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.
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.