Historically, Medicare has used the “pay and chase” method, which means claims are paid and then investigated later to identify any improper or fraudulent payments. This method has enabled providers to easily file fraudulent claims and continue to operate. The Fraud Prevention System was put into place by CMS in 2011, which analyzes data to identify potentially fraudulent claims. Pre-payment review audits are one method the FPS utilizes to identify fraudulent claims. When the test pilot of the pre-payment review program was launched half of the providers involved showed a change in their billing patterns. Although CMS is still primarily relying on the “pay and chase” method other methods are also used to ensure high risk providers are not enrolled in the Medicare program. Routine site visits (some unannounced), periodic licensure verification, fingerprinting of owners, and criminal background checks have also been put into place which resulted in the purging of 500,000 providers from the Medicare program. With 100,000 Americans becoming eligible for Medicare every day, it is of utmost importance that CMS further strengthen their Fraud Prevention System.The most common, but less publicized cases of fraud and abuse are violations of the False Claims Act (FCA). Violations of the FCA include, but are not limited to: billing for services not provided, billing for too many units of service, billing for incorrect procedure codes which results in higher reimbursement, and filing of claims with lack of medical necessity. In order to prove a violation of the FCA has occurred, a prosecuting attorney must show evidence that the accused intended on committing the fraudulent act and should have been aware that it was wrong. Also added to the list of violations included in the FCA was the act of not repaying funds internally identified as overpayments. To some providers, identifying overpayments may not be blatantly obvious due to the complexity of claim filing. Some providers do intentionally misfile claims. Employees who are witness to such acts and come forward are called whistleblowers. The FCA also allows whistleblowers to provide information regarding false claims. Any funds recovered are shared with the whistleblowers as an incentive.