Master Beneficiary Summary File

The Master Beneficiary Summary File includes several segments.

Base (A/B/D) segment: This segment includes beneficiary enrollment information, such as the beneficiary unique identifier, state and county codes, zipcode, date of birth, date of death, sex, race, age, monthly entitlement indicators (A/B/D), reasons for entitlement, and monthly managed care indicators (yes/no). As of 2006, it also includes variables specific to enrollment in Part D.

Chronic Conditions segment: This segment includes 27 chronic condition data warehouse flags called CCW Flags. This includes 6 new chronic conditions in addition to the 21 chronic conditions previously defined. For more information about the CCW Flags, please see the CCW User Guide.

Cost & Utilization segment: This segment includes summarized information about the service utilization and Medicare payment amounts by file type.

National Death Index (NDI) segment:
This segment includes the National Death Index cause of death information. This is available for all Medicare beneficiaries from 1999-2008 and for Medicaid recipients from 1999-2007.  There are no plans to update the NDI segment.

Base (A/B/D) Segment

Availability: 
CY 1999 -2012

The Part D variables in the Base segment are available for years 2006 and forward only.

Next Release Date: 
January, 2015

Chronic Conditions Segment

Availability: 
CY 1999-2012
Next Release Date: 
January, 2015

Cost and Use Segment

Availability: 
CY 1999-2012

The mid-year Cost and Use segment, which is available in the Fall, will not include Part D claims information.

Next Release Date: 
January, 2015

National Death Index Segment

Availability: 
CY 1999 - 2008

This is available for all Medicare beneficiaries from 1999-2008 and for Medicaid recipients from 1999-2007.

Data File Classification