Many methodological debates in microeconometrics are driven by the tension between ``what we can get'' (identification) and ``what we want'' (parameters of interest). This paper proposes to consider models of policy choice which allow for a joint formal discussion of both issues. We consider a...

Despite the fact that the average American student is absent more than two weeks out of every school year, most research on the effect of instructional time has focused not on attendance but on the length of the school day or year. Student and school fixed effects models using Massachusetts...

Tournaments are widely used in the economy to organize production and innovation. We study individual data on 2,775 contestants in 755 software algorithm development contests with random assignment. The performance response to added contestants varies non-monotonically across contestants of...

Optical bound states in the continuum (BICs) have recently been realized in photonic crystal slabs, where the disappearance of out-of-plane radiation turns leaky resonances into guided modes with infinite lifetimes. We show that such BICs are vortex centers in the polarization directions of...

Complex animal behaviors are built from dynamical relationships between sensory inputs, neuronal activity, and motor outputs in patterns with strategic value. Connecting these patterns illuminates how nervous systems compute behavior. Here, we study Drosophila larva navigation up temperature...

This paper proposes an estimator and develops an inference procedure for the number of roots of functions which are nonparametrically identified by conditional moment restrictions. It is shown that a smoothed plug-in estimator of the number of roots is super-consistent under i.i.d. asymptotics,...

We estimate the causal effect of sovereign default on the equity returns of Argentine firms. We identify this effect by exploiting changes in the probability of Argentine sovereign default induced by legal rulings in the case of Republic of Argentina v. NML Capital. Because the legal rulings...