We evaluate a randomized outreach study in which the IRS sent informational letters to 3.9 million households that paid a tax penalty for lacking health insurance coverage under the Affordable Care Act. Drawing on administrative data, we study the effect of this intervention on taxpayers subsequent health insurance enrollment and mortality. We find the intervention led to increased coverage during the subsequent two years and reduced mortality among middle-aged adults over the same time period. The results provide experimental evidence that health insurance coverage can reduce mortality in the United States.

provided outstanding research assistance. The views and opinions expressed in this paper are those of the authors and do not necessarily represent the position of the Treasury Department or any agency of the United States. This paper was reviewed by the Treasury Department prior to release to ensure compliance with rules governing the confidentiality of taxpayer return information. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

Internal Revenue Service data indicate that $4.4 billion in excess EITC was claimed for tax year 1994, largely due to violations of the qualifying child eligibility criteria. I find that the probability of misreporting a child is increasing in the size of the EITC and tax benefit. The estimated effect of the EITC on noncompliance is statistically significant, but modest in size. Reducing the size and scope of the EITC could improve compliance somewhat, but it would also reduce benefits to compliant taxpayers. Efforts to reduce the frequency of unintentional errors and enhance the effectiveness of enforcement activities might bring about greater improvements in EITC error rates, at a lower cost to compliant taxpayers.

These taxable income levels will be indexed for inflation after 2008. In addition, the Act decreased the tax rates above 15 percent, effective January 1, 2001, as follows: The overall limitation on itemized deductions and the personal exemption phase-out will be reduced by one-third

Taxpayers may be eligible for certain tax benefits if they support or live with their children. Each benefit uses a unique definition of child, partly because the provisions address different tax and social policy goals. Other factors, including piecemeal efforts at tax simplification and complicated family structures, contribute to complexity and increase compliance burdens and noncompliance. A consensus is growing that the definition of child can be simplified without sacrificing important policy goals. Proposals to create a uniform definition of child are similar. The differences between the proposals highlight trade-offs that must be made between simplification and other policy objectives.