The recent literature on instrumental variables (IV) features models in which agents sort into treatment status on the basis of gains from treatment as well as on baseline-pretreatment levels. Components of the gains known to the agents and acted on by them may not be known by the observing...

Italy and Germany have similar geographical differences in productivity - North more productive than South in Italy; West more productive than East in Germany - but have adopted different models of wage bargaining. Italy sets wages based on nationwide contracts that allow for limited local wage...

We investigate how and why the productivity of a worker varies as a function of the productivity of her co-workers in a group production process. In theory, the introduction of a high productivity worker could lower the effort of incumbent workers because of free riding; or it could increase the...