The MedPAR file contains information about inpatient (IP) hospital and skilled nursing facility (SNF) stays that were covered by Medicare.  MedPAR records are created by rolling up information for a single stay from individual IP and SNF claims. The data on these claims was originally submitted on the CMS 1450 or UB04.

The Outpatient file contains fee-for-service (FFS) claims submitted by institutional outpatient providers. Examples of institutional outpatient providers include hospital outpatient departments, rural health clinics, renal dialysis facilities, outpatient rehabilitation facilities, comprehensive outpatient rehabilitation facilities, Federally Qualified Health Centers and community mental health centers. The file includes facility charge amounts.

This file is based on information from the CMS form 1450 (UB04).

The Carrier File includes fee-for-service claims submitted by professional providers, including physicians, physician assistants, clinical social workers, nurse practitioners.

Claims for some organizational providers, such as free-standing facilities are also found in the Carrier Claims File.  Examples include independent clinical laboratories, ambulance providers, free-standing ambulatory surgical centers and free-standing radiology centers.

Researchers rarely use this file alone.

This file is based on information from the CMS claim form 1500.

The Medicare Fee-for-Service  Skilled Nursing Facility (SNF) claim file contains information from paid bills submitted by SNF institutional facility providers. Skilled nursing care is the only level of nursing home care that is covered by the Medicare program.

The information on the file records is based on the CMS form 1450 (UB04).

The Durable Medical Equipment (DME) file contains fee-for-service claims submitted by Durable Medical Equipment suppliers to the DME Medicare Administrative Contractor (MAC).

The Hospice file contains claims submitted by Medicare hospice providers. Records are included in the file regardless of whether the beneficiary is enrolled in fee-for-service (FFS) Medicare or Medicare Advantage (Medicare managed care.) 

This file is based on information from the CMS form 1450 (UB04).

The Medicare Inpatient (Encounter) file contains Medicare Advantage plan records for inpatient hospital stays.

The Medicare Outpatient (Encounter) file contains Medicare Advantage plan records from a variety of outpatient providers. Examples of institutional outpatient providers include hospital outpatient departments, rural health clinics, renal dialysis facilities, outpatient rehabilitation facilities, comprehensive outpatient rehabilitation facilities, Federally Qualified Health Centers and community mental health centers.

The Medicare Carrier (Encounter) file includes Medicare Advantage plan records for professional providers, including physicians, physician assistants, clinical social workers, nurse practitioners.

Records for some organizational providers are also found in the Carrier (Encounter) file. Examples include independent clinical laboratories, ambulance providers, freestanding ambulatory surgical centers and freestanding radiology centers.

Researchers rarely use this file alone.

The Medicare Skilled Nursing Facility (Encounter) file includes Medicare Advantage plan records for skilled nursing facility stays. Skilled nursing care is the only level of nursing home care that is covered by the Medicare program.

The Medicare Durable Medical Equipment (Encounter) file includes Medicare Advantage plans records for medical supplies.

The Medicare Home Health Agency (Encounter) file includes Medicare Advantage (MA) plan records for home health agency services.

The Risk Score Files are created from the final CMS risk adjustment model outputs for a payment year. These risk scores are used to adjust CMS payments to Medicare Advantage (Part C) plans to account for differences in relative costs among plan enrollees. At this time, only Payment Year (PY)14 risk score files are available for research use.  

Please see the Medicare Managed Care Manual, Chapter 7 for a discussion of risk adjustment in the Medicare Advantage program.

When a Medicare beneficiary with Part D coverage fills a prescription, the prescription drug plan submits a record to CMS. The PDE file includes all transactions covered by the Medicare prescription drug plan for both Prescription Drug Plans (PDPs) and Medicare Advantage Prescription Drug Plans (MA-PDs).

The Medicare Part D Drug Characteristics file refers to a set of variables that are appended to the Medicare Part D Event file (PDE). Researchers need to request the specific variables required for their study and CMS must approve the release.

The Medicare Part D Formulary file is a suite of five sub-files: Formulary, Excluded Drug, Over-the-Counter Drug, Indication-based Formulary, and Part D Senior Savings (PDSS) Model that contain information on how the plan covers the prescription drugs filled (as described in the Part D Drug Event (PDE) file.

The Part D Pharmacy Characteristics file provides information about the pharmacy identified as the source of the drug for each Part D Event (PDE) prescription fill record.

The Plan Characteristics file contains Medicare Advantage plan and Prescription Drug Plan information separated into six subfiles.

The subfiles are:

• Plan Base
• Premium
• Tier
• Service Area
• Plan Crosswalk
• SNP Contract

The Medicare Part D Prescriber Characteristics file contains descriptive information for the prescriber identified on a Part D Event file record.

This file includes beneficiary-level information for participants in the Part D Medication Therapy Management (MTM) program, required of CMS Part D plans. Eligible beneficiaries include those enrolled in Part D plans with multiple chronic disease, those taking multiple Part D drugs and those likely to have expenditures exceeding a specified level as described by federal regulations.

This Medicare Part D file identifies beneficiaries covered by the Low Income Subsidy (LIS) program for Part D Plan enrollment. 

The Long Term Care Minimum Data Set (MDS) is a health status screening and assessment tool used for all residents of long term care nursing facilities certified to participate in Medicare or Medicaid, regardless of payer. The assessment is also required for Medicare payment of skilled nursing facility stays. Assessment data for Skilled Nursing Swing Beds 3.0 is included in a separate file, MDS version 3.0 was implemented on October 1, 2010, replacing version 2.0.

The Home Health Outcome and Assessment Information Set (OASIS) contains data items developed to measure patient outcomes and for improve home health care. The OASIS assessments are required of all home health agencies certified to accept Medicare and Medicaid payments.

The Inpatient Rehabilitation Facility Patient Assessment Instrument (IRF-PAI) is collected on all Medicare patients who receive services from an inpatient rehabilitation unit or hospital. The data collected for IRF-PAI are used to measure quality of care.