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 is assigned a unique, unidentifiable link key, which allows researchers to easily merge data files and perform relevant analyses across different claim types, enrollment files, Part D event data, assessment data, and other CCW file types. CCW data files are available upon request from CMS. While the file record layouts provided below are the standard file record layouts for all CCW data requests, data may be requested for a variety of cohorts (e.g., specific to a research study design, national 5% sample, specific state or other demographic, etc.).

The CCW claims data files have been streamlined to include only those variables determined by CMS to be of value and useful for research or analytic 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 file record layouts listed below provide variable descriptions, variable format, and length for those variables included in the CCW data files. For additional information regarding data file availability, please refer to the Research Identifiable File Availability.

Medicare Claims

Data File Availability Record Layout Codebook
Medicare Fee-For-Service Claims 1999-2021 Record Layout Codebook
Medicare Encounter Records 2015-2020 Record Layout Codebook
MedPAR Data Dictionary 1999-2021 Record Layout Codebook

Medicare Enrollment

Data File Availability Record Layout Codebook
Master Beneficiary Summary - Base (A/B/C/D) 2006-2021 Record Layout Codebook
Master Beneficiary Summary - Base (A/B/D) 1999-2005 Record Layout Codebook
Master Beneficiary Summary - National Death Index (NDI) 1999-2021 Preliminary Record Layout Codebook
Master Beneficiary Summary - 27 CCW Chronic Conditions 1999-2021 Record Layout Codebook
Master Beneficiary Summary - 30 CCW Chronic Conditions 2017-2021 Record Layout Codebook
Master Beneficiary Summary - Other Chronic or Potentially Disabling Conditions 2000-2021 Record Layout Codebook
Master Beneficiary Summary - Cost and Use 1999-2021 Record Layout Codebook
Plan Characteristics File (formerly titled Part D Plan Characteristics) 2015-2021 Record Layout Codebook
Healthcare Effectiveness Data and Information Set (HEDIS) 2015-2016 Record Layout No file 
Medicare Risk Score Files 2014 Record Layout Codebook

Medicare Part D

Data File Availability Record Layout Codebook
Part D Event / Drug Characteristics Files 2006-2021 Record Layout Codebook
Part D Plan Characteristics Files 2007-2014 Record Layout Codebook
Part D Plan Characteristics Files 2006 Record Layout No file 
Part D Pharmacy Characteristics Files 2006-2021 Record Layout Codebook
Part D Prescriber Characteristics Files 2006-2021 Record Layout Codebook
Part D Formulary Files 2010-2021 Record Layout Codebook
Part D Medication Therapy Management Files 2013-2020 Record Layout Codebook
Part D Plan Election Type Beneficiary Summary Files 2007-2020 Record Layout Codebook

Accountable Care Organizations (ACOs) and Other Innovation Center Initiatives

Data File Availability Record Layout Codebook
Shared Savings Program (SSP) - Beneficiary File 2013-2021, 
2022 Preliminary and Q1-Q3
Record Layout No file 
Shared Savings Program (SSP) - Provider File 2013-2021, and
2022 Preliminary
Record Layout No file 
Next Generation ACO - Beneficiary and Provider File - Beneficiary and Provider File 2016-2021 Record Layout No file 
Pioneer 2012-2014 Record Layout Codebook
Comprehensive End Stage Renal Disease Care Model - Beneficiary and Provider File Q4 2015-2020 Record Layout No file 
CMMI Model Data Sharing - Entity, Provider, Beneficiary 2016-2022 Record Layout No file 

Assessment

Data File Availability Record Layout Codebook
IRF-PAI 1999-2020 Record Layout No file 
MDS 3.0 October 2010-2020 Record Layout No file 
Swing Bed 3.0 October 2010-2020 Record Layout No file 
OASIS 1999-2020 Record Layout No file 
SPADE 2018 Record Layout No file 
MDS 2.0 1999-Sept. 2010 Record Layout No file 
Swing Bed 2.0 1999-Sept. 2010 Record Layout No file 

Medicaid

Data File Availability Record Layout Codebook
T-MSIS Analytic File (TAF) Demographic and Eligibility 2014-2021 Record Layout Codebook
T-MSIS Analytic File (TAF) Claims 2014-2021 Record Layout Codebook
T-MSIS Analytic File (TAF) Annual Plan 2014-2021 Record Layout Codebook
T-MSIS Analytic File (TAF) Annual Provider 2014-2021 Record Layout Codebook
Medicaid Analytic eXtract (MAX) - CCW 1999-2015 Record Layout No file 
Medicaid Enrollee Supplemental File (MESF) – Chronic Conditions 1999-2013 Record Layout No file 
Medicaid Enrollee Supplemental File (MESF) - National Death Index (NDI) 1999-2020 Record Layout No file 

Useful Medicaid Analytic eXtract (MAX) Data Validation Tables, Data Anomalies Reports, and other data documentation about file content by state and year are also available for review on the Centers for Medicare & Medicaid Services (CMS) website.

Medicare-Medicaid Linked Enrollee Analytic Data Source (MMLEADS)

Data File Availability Record Layout Codebook
MMLEADS 2016 Record Layout Codebook
MMLEADS 2006-2012 Record Layout No file 

The MMLEADS Public Use File (PUF) is available on the CMS website.

Other Data Files

Data File Availability Record Layout Codebook
Medicare Data on Provider Practice and Specialty (MD-PPAS) 2008-2020 CMS Data Layout No file