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.
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Introductory
Articles
Differences between RIF, LDS, and PUF Data Files
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,…
Federal Regulations Governing the Release of CMS Data
This article describes the Federal Regulations that govern the release of CMS data for research.
Strengths and Limitations of CMS Administrative Data in 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…
Popular
Articles
How to Identify Hospital Claims for Emergency Room Visits in the Medicare Claims Data
This article provides guidance on how to identify hospital emergency room claims from the Medicare files.
Diagnosis and Procedure Coding Resources
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…
CMS Cell Size Suppression Policy
To describe the CMS cell size suppression policy and provide examples of common scenarios and possible options.

Featured Article

Provider Variables in Medicare Fee-for-Service and Encounter Data
There are many different provider variables in the Medicare Fee-for-Service (FFS) Claims and Encounter data. Researchers are often interested in the performing NPI and/or the facility CCN or organizational NPI, but other variables are sometimes…
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Medicare Data Finder and Crosswalk Files
This article provides a link and overview of the document on finder and crosswalk files written by the CMS data distributor, HealthAPT.
Strengths and Limitations of CMS Administrative Data in 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 requesting and using the data.
Difference between Target Date and Submission Date in the Minimum Data Set (MDS)
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.
Missing Values in the MDS
Values that are "missing" in the Minimum Data Set (MDS) nursing home assessment can be represented by several different symbols. While all of these symbols represent that a value is "missing," the specific symbol indicates the specific reason why the value is missing.
Missing Data on Pain Items in MDS 3.0 Nursing Home Assessment
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…