How do exporters enter and expand their product scope and geographical presence? We show that exporters add products and countries sequentially, in an interdependent process. This process can be explained by a mechanism where new exporters are uncertain about the profitability of their products in different markets, but learn it as they start to export. Exploiting disaggregated data on French exporters, we find empirical evidence consistent with such a mechanism, where firms learn from their initial export experiences and adjust their sales, number of products and destination countries accordingly. Our results indicate that part of the learning is firm-specific, and not merely product- or market-specific. Furthermore, we find that firms tend to expand in the sub-extensive margin first by widening product scope within a destination and later by entering new destinations; and that firms' core products are particularly resilient despite being used to ``test the waters when entering additional countries.

We consider a population of students with heterogeneous characteristics, and examine the dual design problem consisting of (a) allocating students to schools and (b) choosing how to grade students in school, with a view to optimizing students' incentives to work hard. We show that any optimal school design exhibits stratification, and more lenient grading at the top-tier schools than at the bottom-tier schools. Our results highlight a novel trade-off between the size of the pie and its equal division in the context of school design.

A principal designs an information structure and chooses transfers to an agent that are contingent on the action of a receiver. The principal faces a trade-off between, on the one hand, designing an information structure maximizing non-monetary payoffs, and on the other hand, minimizing the information rent that must be conceded to the agent in order to implement the information structure which the principal designed. We examine how this trade-off shapes communication. Our model can be applied to study the relationship between, e.g.: political organizations and the public relations companies that campaign on their behalf, firms and the companies marketing their products, consultancies and the analysts they employ.