Critics argue that electronic voting is vulnerable to fraud. We test whether voting technology affected electoral outcomes in the 2000 and 2004 presidential elections. We find a positive correlation between use of electronic voting and George Bush vote share. The effect could have been large...

Empirical researchers interested in the causal effect of the endogenous regressor often use instrumental variables. When few valid instruments are available, they typically estimate restricted specifications that impose uniform per unit treatment effects, even when these effects are likely to...

Most Americans are now in some form of managed care plan that restricts access to services in order to reduce costs. It is difficult to determine whether these restrictions affect health because individuals and firms self-select into managed care. We investigate the effect of managed care using...

We estimate the effect of extreme weather on life expectancy in the United States. Using high-frequency data, we find that both extreme heat and cold result in immediate increases in mortality. The increase in mortality following extreme heat appears mostly driven by near-term displacement,...

This paper studies the evolution of income concentration in Japan from 1886 to 2005 by constructing long-run series of top income shares and top wage income shares, using income tax statistics. We find that (i) income concentration was extremely high throughout the pre-WWII period during which...

We study social interactions in the initiation of sex and other risky behaviors by best friend pairs in the Add Health panel. Focusing on friends with minimal experience at the baseline interview, we estimate bivariate ordered-choice models that include both peer effects and unobserved...

Despite intensive scrutiny, the effects of Medicaid expansions on the health insurance status of low-income children remain controversial. We reexamine the effects of the two largest federally mandated expansions which offered Medicaid coverage to low-income children in specific age ranges and...

Defined contribution pensions in many postsecondary institutions are funded by a combination of an employer premium and a mandatory employee premium. Individuals can also contribute to a supplemental savings account. Holding constant total compensation, standard reasoning suggests that...