We develop a model of a city populated by heterogeneous agents. Agents self-select into entrepreneurship, and entrepreneurs set up firms which hire workers. We characterize the equilibrium matching between firms and workers, as well as the within-city assignment of agents to locations. We then...

We study the screening problem of a firm that needs to hire a worker to produce output and that observes neither the productive ability nor the intrinsic motivation of the job applicant. We completely characterize the set of optimal contracts according to whether motivation or ability is the...