Econometric analyses of treatment response commonly use instrumental variable (IV) assumptions to identify treatment effects. Yet the credibility of IV assumptions is often a matter of considerable disagreement, with much debate about whether some covariate is or is not a "valid instrument" in...

Despite dozens of studies, research on crime in the United States has struggled to reach consensus about the impact of right-to-carry (RTC) gun laws. Empirical results are highly sensitive to seemingly minor variations in the data and model. How then should research proceed? We think that policy...

Researchers have long used repeated cross sectional observations of homicide rates and sanctions to examine the deterrent effect of the adoption and implementation of death penalty statutes. The empirical literature, however, has failed to achieve consensus. A fundamental problem is that the...

USDA operates several food assistance programs aimed at alleviating food insecurity. We study whether participation in both SNAP and WIC alleviates food insecurity compared with participation in SNAP alone. We bound underlying causal effects by applying nonparametric treatment effect methods...