When a Medicare beneficiary with Part D coverage fills a prescription, the prescription drug plan submits a record to CMS. The Part D Event (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).
Important changes to the PDE file beginning October 2026:
Standard Layout: The PDE file is released in a standard format. The PDE standard layout includes the variables formerly available in the Drug Characteristic File, which is no longer a stand-alone data product.
VRDC Users with PDE Production Library/Schema Access: PDE datasets for service years earlier than 2026 remain in the original “themed” layouts.
Custom Extract Recipients (VRDC or shipped): For custom PDE extract requestors, CCW creates extracts in the standard layout for all years ordered. Requestors are not required to select individual PDE variables and provide variable-level justifications.
Quarterly Files: CMS releases PDE data quarterly datasets starting with the 2026 service year. The quarterly Part D data products are produced after a three-month maturity run-out, following the same cadence as the quarterly Master Beneficiary Summary File and Original Medicare claims datasets. For example:
- Q1 2026 (January – March 2026) PDE was produced in July 2026
- Q2 2026 (April – June 2026) PDE was produced in October 2026
What does this file include? (variable highlights)
- Service date
- Product Service ID (NDC code)
- Quantity dispensed
- Days supply
- Cost
- Payment
- Brand name
- Generic name
- Strength
- Form of the drug
- Linkage variables:
- Plan Contract ID, Plan Benefit Package ID for linkage to Plan Characteristics file
- Beneficiary Id for linkage to Medicare enrollment, MTM and Plan Election characteristics files, Original Medicare utilization, and assessment data for Medicare and Medicaid
- Formulary identifier and formulary drug identifier for linkage to the Part D Formulary Characteristics files
- CCW Pharmacy ID or the NCPDP_ID for linkage to the Pharmacy Characteristics file
- CCW-assigned Prescriber Identifier for linkage to the Prescriber Characteristics file
Why do researchers request this file?
- Studies that include prescription drugs as a treatment of interest
- Research comparing outcomes of treatment
Special considerations
- These files do not have information on drugs given during hospitalizations or which are paid under other auspices (e.g., hospice)
- 2006-2025 PDE data in the VRDC will not be rerun in the standard layouts, so the drug characteristics data will continue to be a separate file for those service years.
