This paper analyzes private anti-fraud enforcement under the False Claims Act, which compensates whistleblowers for litigating against healthcare providers who overbill the US government. I conduct several case studies of successful whistleblower lawsuits concerning Medicare fraud, pairing new legal data with large samples of Medicare claims. I estimate that deterrence from $1.9 billion in whistleblower settlements generated Medicare cost savings of nearly $19 billion, while imposing low costs on the government. These results suggest private enforcement is a cost-effective way to combat public expenditure fraud.

The Medicare hospice program is intended to provide palliative care to terminal patients, but patients with long stays in hospice are highly profitable, motivating concerns about overuse among the Alzheimer's and Dementia (ADRD) population in the rapidly growing for-profit sector. We provide the first causal estimates of the effect of for-profit hospice on patient spending using the entry of for-profit hospices over 20 years. We find hospice has saved money for Medicare by offsetting other expensive care among ADRD patients. As a result, policies limiting hospice use including revenue caps and antifraud lawsuits are distortionary and deter potentially cost-saving admissions. (JEL H51, I11, I12, I18, J14, L84)

We study the effectiveness of pay-and-chase lawsuits and upfront regulations for combating health care fraud. Between 2003 and 2017, Medicare spent $7.7 billion on 37.5 million regularly scheduled ambulance rides for patients traveling to and from dialysis facilities even though many did not satisfy Medicare's criteria for receiving reimbursements. Using an identification strategy based on the staggered timing of regulations and lawsuits across the US, we find that adding a prior authorization requirement for ambulance reimbursements reduced spending much more than pursuing criminal and civil litigation did on their own. We find no evidence that prior authorization affected patients' health.