You are here
Home > Data Sources > Chronic Conditions Data Warehouse

Chronic Conditions Data Warehouse

CMS Chronic Conditions Data Warehouse Logo
Print Friendly, PDF & Email


The CMS Chronic Conditions Data Warehouse (CCW) provides researchers with Medicare and Medicaid beneficiary, claims, and assessment data linked by beneficiary across the continuum of care. In the past, researchers analyzing data files were required to perform extensive analysis related to beneficiary matching, deduplication, and merging of the files in preparation for their study analysis. With the CCW data, this preliminary linkage work is already accomplished and delivered as part of the data files sent to researchers.

The Centers for Medicare & Medicaid Services (CMS) launched the Chronic Conditions Data Warehouse (CCW), a research database, in response to the Medicare Modernization Act of 2003 (MMA). Section 723 of the MMA outlined a plan to improve the quality of care and reduce the cost of care for chronically ill Medicare beneficiaries. In addition to chronic conditions, the CCW supports health policy analysis and other CMS initiatives. The CCW data are linked by a unique, unidentifiable beneficiary key, which allows researchers to analyze information across the continuum of care.

Data Availability

CCW contains the following 100% Medicare files for years 1999 – 2011:

  • Fee-for-service institutional and non-institutional claims
  • Enrollment/eligibility
  • Assessment data

100% Medicaid files for years 1999-2009
100% Part D Prescription Drug Event data for years 2006-2012

  • Plan characteristics
  • Pharmacy characteristics
  • Prescriber characteristics
  • Formulary file – beginning with year 2010


Are you using this data source? Share your experience with it by leaving a reply below!

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.