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 an overview of the Centers for Medicare & Medicaid Services' (CMS') Price (Payment) Standardization process, as well as provide methodological documentation that explains how the standardized claim payment amounts for Medicare Part A, Part B, and Part D claims are calculated.
To describe the CMS policy that prohibits non-US based researchers from accessing identifiable CMS data (RIF and LDS) and provide examples of common scenarios.
Availability of provider variables Provider variable completeness Provider variable definitions
Along with claims at the individual beneficiary (single enrollee/provider/visit) level, state Medicaid programs also submit service tracking claims which record lump sum payments to providers or managed care plans. These data are a new enhancement to the TAF RIF, and researchers have the option of requesting these claims along with TAF claims data. This article describes service tracking claims in TAF RIF data and considerations for researchers.
The purpose of this article is to describe how to use the Medicare managed care enrollment information found in the Medicare Beneficiary Summary File (MBSF) Research Identifiable File (RIF) or Denominator in the Limited Data Set (LDS). Medicare managed care is sometimes also called Medicare Advantage, Medicare Part C or Medicare + Choice.
This article presents the data options available to researchers studying the End-Stage Renal Disease (ESRD) population. 
Medicare-paid observation stays may be found in the Medicare Outpatient, Inpatient, or MedPAR files. This article describes how to identify observation stays that appear in each as defined by CMS billing guidance.
For data years 2006 and forward, dually eligible Medicare beneficiaries are identified in the Medicare Master Beneficiary Summary File, Base segment. Initially available only as a RIF, this file was released as an LDS file in 2016. The monthly variable “Medicare-Medicaid Dual Eligibility” identifies dual status. Dual eligibles are also identified in the Medicaid Analytic Extract (MAX) Personal Summary (PS) file.
Doctoral students may request CMS data for their dissertation project. Students should consider several factors when deciding which type of data to use. This article presents considerations and resources for students interested to request CMS Research identifiable data.
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.
The Medicare Hospital Service Area File is one of the few CMS non-identifiable files that can be opened in Microsoft Excel. The article describes the steps to import the file into Excel.