Content and Documentation
The CCW data files were designed to facilitate research across the continuum of care, using data files that could be easily merged and analyzed by beneficiary. Each beneficiary in the CCW sample is assigned a unique, unidentifiable link key, which allows researchers to easily merge data files and perform relevant analyses.
The following CCW data files are available upon request from CMS (see Requesting Data tab) for 21 predefined chronic condition cohorts or other researcher-defined populations.
| Data File | Description |
| Medicare fee-for-service institutional claims | Institutional claims for hospital, outpatient, skilled nursing facility, hospice, and home health agency settings |
| Medicare fee-for-service non-institutional claims | Non-institutional claims for Carrier [physician/supplier] and Durable Medical Equipment Regional Carrier [DMERC] |
| Minimum Data Set (MDS) | Assessment data from nursing facilities |
| Outcome and Assessment Information Set (OASIS) | Assessment data from home health agencies |
| Inpatient Rehabilitation Facility Patient Assessment Instrument (IRF-PAI) | Assessment data from inpatient rehabilitation facilities |
| Swing bed assessments | Assessment data from swing bed facilities |
| Beneficiary Summary File | Summary of beneficiary demographic information for beneficiaries included in the requested data files |
| Chronic Condition Summary File | Summary of beneficiary chronic conditions by year |
CCW User Manual
Read more about the CCW by viewing the 
CCW User Manual. This manual provides users with information that may be helpful in understanding and analyzing the CCW data including descriptions of the CCW population, chronic condition definitions, and limitations of the data.
CCW File Record Layouts
The CCW claims data files have been streamlined to include only those variables determined by CMS to be useful for research purposes. The data files delivered from the CCW contain a subset of the original source files. Variables used infrequently or not applicable to a particular setting have been removed. The following file record layouts provide variable descriptions, variable format, and length for those variables included in the CCW data files:
For information on requesting data, please visit our requesting data section.
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