The federal government provides generous tax subsidies for retirement saving in 401(k)s and IRAs. The subsidies are designed to increase household saving and retirement income security, important national goals. The estimated cost, however, exceeds $100 billion a year in lost revenue to the...

Do retirement savings policies--such as tax subsidies or employer-provided pension plans--increase total saving for retirement or simply induce shifting across accounts? We revisit this classic question using 45 million observations on wealth for the population of Denmark. We find that a...

The probability that an incumbent in the United States House of Representatives is reelected has risen dramatically over the last half-century. It now stands at more than 98%. A number of authors and commentators claim that this rise is due to an increase in bipartisan gerrymandering in favor of...

Value-added (VA) models measure the productivity of agents such as teachers or doctors based on the outcomes they produce. The utility of VA models for performance evaluation depends on the extent to which VA estimates are biased by selection, for instance by differences in the abilities of...

Are teachers' impacts on students' test scores ("value-added") a good measure of their quality? This question has sparked debate partly because of a lack of evidence on whether high value-added (VA) teachers who raise students' test scores improve students' long-term outcomes. Using school...

Are teachersʼ impacts on studentsʼ test scores ("value-added") a good measure of their quality? One reason this question has sparked debate is disagreement about whether value-added (VA) measures provide unbiased estimates of teachersʼ causal impacts on student achievement. We test for bias...

Using 41 million observations on savings for the population of Denmark, we show that the impacts of retirement savings policies on wealth accumulation depend on whether they change savings rates by active or passive choice. Subsidies for retirement accounts, which rely upon individuals to take...

We develop a new method of estimating the impacts of tax policies that uses areas with little knowledge about the policy's marginal incentives as counterfactuals for behavior in the absence of the policy. We apply this method to characterize the impacts of the Earned Income Tax Credit (EITC) on...