A common working file (CWF) is a tool used by the Centers for Medicare & Medicaid Services (CMS) to maintain national Medicare records for individual beneficiaries enrolled in the program. The system is used to determine the eligibility of patients and to monitor the appropriate usage of Medicare benefits.
The common working file retains a record (which is automatically created by the government upon enrolling in Medicare programs) that documents claim history, benefits and eligibility in order to expedite the prepayment process. In addition, the record contains important personal health information (PHI), such as date of birth and/or death, information about secondary or additional insurance coverage and whether the patient has opted for palliative care.
The common working file centralizes information and eases the billing and claims process for Medicare recipients. The tool also ensures the correct level and administration of Medicare benefits in an effort to reduce instances of Medicare fraud.