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Rehabilitation Dataset Directory: Dataset Profile

Dataset: Master Beneficiary Summary File Base (A/B/C/D) (MBSF)

Basic Information
Dataset Full Name Master Beneficiary Summary File Base (A/B/C/D)
Dataset Acronym MBSF

The Master Beneficiary Summary File (MBSF) Base (a/b/c/d*) contains information on Medicare enrollees including demographics (e.g., age, gender, race, and type of residence) and enrollment information (e.g., original reason for enrollment under Medicare, current reason for enrollment under Medicare, dual eligibility status, and monthly entitlement indicators) as well as the enrollment status of each Medicare beneficiary enrollee during a calendar year. The file also includes variables specific to enrollment benefits, monthly indicators for Medicare Advantage plan enrollment, and State Reported Dual Eligibility Status (a State Buy-In indicator). 

The Master Beneficiary Summary File Base provides basic characteristics of the Medicare population and serves as the denominator file for the four MBSF related data segments available that can be linked to this base data:

* Part A: Hospital Insurance, Part B: Medical Insurance, Part C: Medicare Advantage  (Medicare managed care plans), Part D: Prescription Drug Program plan

Note: the MBSF replaced the Medicare Beneficiary Summary File as of 03/2012

Key Terms Medicare, Demographics, Beneficiary, Enrollment 
Study Design Longitudinal
Data Type(s) Administrative
Sponsoring Agency/Entity

Department of Health and Human Services (HHS):

Centers for Medicare and Medicaid Services (CMS)

Health Conditions/Disability Measures
Health Condition(s)

Note: The following measures are not directly available in the MBSF but are through the linkable files :Chronic Condition Segment (CCS) and the Other Chronic or Potentially Disabling Conditions segment contain the disability and conditions information):

Chronic Condition Segment (CCS):

The health conditions data in the CCS contains conditions that are specifically tagged in this data directory as well as 27 specific chronic health conditions:

Alzheimer's/dementia, Arthritis, Blood disorder, Cancer, Depression, Diabetes, Eye diseases , Heart attack, ICD-9/10 diagnostic codes, Kidney/renal condition, Orthopedic conditions, Osteoporosis, Stroke, Thyroid disease

The 27 specific chronic health conditions identified in CCS:

Acquired Hypothyroidism, Acute Myocardial Infarction, Alzheimer's Disease, Alzheimer's Disease, Related Disorders, or Senile Dementia, Anemia, Asthma, Atrial Fibrillation, Benign Prostatic Hyperplasia, Colorectal Cancer, Endometrial Cancer, Breast Cancer, Lung Cancer, Prostate Cancer, Cataracts, Chronic Kidney Disease, Chronic Obstructive Pulmonary Disease (COPD), Depression, Diabetes, Glaucoma, Heart Failure, Hip / Pelvic Fracture, Hyperlipidemia, Hypertension, Ischemic Heart Disease, Osteoporosis, Rheumatoid Arthritis/Osteoarthritis, Stroke/Transient Ischemic Attack

Complete list of chronic conditions (and criteria used).

Other Chronic or Potentially Disabling Conditions segment:

These additional conditions are available:

ADD/ADHD, Anxiety disorders, Autism spectrum disorders, Bipolar disorder, Body mass index (BMI)/obesity, Cerebral palsy, Chronic pain, Depressive disorders, Epilepsy or seizure disorder, Migraine or frequent headaches, ICD-9/10 diagnostic codes, Multiple sclerosis, Muscular dystrophy, Post traumatic stress disorder (PTSD), Pulmonary disorders, Schizophrenia, Spinal cord injury (SCI), Traumatic brain injury (TBI) 

The 35 specific conditions identified in Other Chronic or Potentially Disabling Conditions segment:
ADHD, Conduct Disorders/and Hyperkinetic Syndrome, Alcohol Use Disorders, Anxiety Disorders, Autism Spectrum Disorders, Bipolar Disorder, Cerebral Palsy, Cystic Fibrosis and Other Metabolic Developmental Disorders, Depressive Disorders, Drug Use Disorders, Epilepsy, Fibromyalgia/Chronic Pain and Fatigue, Human Immunodeficiency Virus and/or Acquired Immunodeficiency Syndrome (HIV/AIDS) , Intellectual Disabilities and Related Conditions, Learning Disabilities, Leukemias and Lymphomas, Liver Disease/Cirrhosis and Other Liver Conditions, Migraine and Chronic Headache, Mobility Impairments, Multiple Sclerosis and Transverse Myelitis, Muscular Dystrophy, Obesity, Other Developmental Delays, Peripheral Vascular Disease (PVD), Personality Disorders, Post-Traumatic Stress Disorder (PTSD), Pressure and Chronic Ulcers, Schizophrenia, Schizophrenia and Other Psychotic Disorders, Sensory - Blindness and Visual Impairment, Sensory - Deafness and Hearing Impairment, Spina Bifida and Other Congenital Anomalies of the Nervous System, Spinal Cord Injury, Tobacco Use, Traumatic Brain Injury and Nonpsychotic Mental Disorders due to Brain Damage, Viral Hepatitis
Disability Measures

Note: The following measures are not directly available in the MBSF but are through the linkable files:

Mental health disability, Visual disability, Hearing disability, Cognitive disability, Intellectual disability, Ambulatory disability,

Learning disabilities

Measures/Outcomes of Interest
Topics Demographic (e.g., age, gender, race, and residential), Enrollment information
Sample Population
Medicare beneficiaries:
  • 100% Medicare: 1999-2016
  • 100% Part C & Part D : 2006-2016
Sample Size/Notes
For calendar year 2016: 
  • Medicare: 57 million
  • Part D: 41.2 million
Unit of Observation Individual/Patient
Continent(s) North America

United States

Geographic Coverage National (U.S.)
Geographic Specificity Zip Code (of beneficiary’s mailing address)
Special Population(s)

Medicare beneficiaries

Data Collection
Data Collection Mode Administrative
Years Collected

1999 - present

Part C and Part D enrollment information:  2006 - present

Data Collection Frequency Quarterly
Strengths and Limitations
  • Very large sample size
  • Files can be requested for a predefined or customized chronic condition cohort
  • Population-based dataset (includes all beneficiaries)
  • Can be linked via unique beneficiary ID to the other Master Beneficiary Summary File (MBSF) segments:
  • Can be used to perform cross-state and within-state comparisons
  • Care must be taken in utilizing the data to calculate population statistics (see Technical Guidance for more information)
  • Requires high computational and data analytical capabilities   
  • Part C and Part D enrollment information are available beginning with the 2006 file year. Years prior to 2006 include an indicator variable for managed care enrollment.
Data Details
Primary Website

Data Access

ResDac CMS Research Identifiable File (RIF) Requests:

MBSF and related segment availability:

Data Access Requirements Data Use agreement, $ Cost
Summary Tables/Reports NA
Data Components
Other Master Beneficiary Summary File (MBSF) segments:
Similar/Related Dataset(s)
Other Master Beneficiary Summary File (MBSF) segments:

Medicare Beneficiary Summary File 1999-2012)

Selected Papers
Other Papers

White papers and presentations Chronic Condition Warehouse (CCW):


Variable listing:

Additional relevant MBSF Base documentation related to the Chronic Condition Warehouse (CCW)

User Documentation:

CCW Medicare Administrative Data User Guide:

Data Dictionaries:

Technical Guidance Documentation:

Study size sample estimator (user can specify parameters and estimator outputs approximate sample available):


What you need to know before you submit a request CMS data:

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The Rehabilitation Research Cross-dataset Variable Catalog has been developed through the Center for Large Data Research & Data Sharing in Rehabilitation (CLDR). The Center for Large Data Research and Data Sharing in Rehabilitation involves a consortium of investigators from the University of Texas Medical Branch, Cornell University's Yang Tan Institute (YTI), and the University of Michigan. The CLDR is funded by NIH - National Institute of Child Health and Human Development, through the National Center for Medical Rehabilitation Research, the National Institute for Neurological Disorders and Stroke, and the National Institute of Biomedical Imaging and Bioengineering. (P2CHD065702).

Other CLDR supported resources and collaborative opportunities:

Acknowledgements: This tool was developed through the efforts of William Erickson and Arun Karpur, and web designers Jason Criss and Jeff Trondsen at Cornell University. Many thanks to graduate students Kyoung Jo Oh and Yeong Joon Yoon who developed much of the content used in this tool.

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