附上两篇Princeton经济系今年的JMP。


I develop and estimate a model of export dynamics featuring self-discovery. The estimated model accounts well for the relationship between growth, survival, and tenure in the export market that is observed in the data for new exporters: (a) continuation rates are increasing with export tenure, and (b) growth rates of export sales are decreasing with export tenure. I use the estimated model to quantify the role of learning in shaping the firm level export decision and to undertake counterfactuals for the effects of export promotion on aggregate trade. I find that: (i) first-time exporters expect to incur losses by serving the foreign market, but the option value generated by the acquisition of more precise information regarding export profitability compensates inexperienced exporters for these losses; (ii) the initial period serving the foreign market provides a crucial learning experience for new exporters, but the discovery stage extends beyond the first year: the value of learning remains positive for the first four years of tenure in the export market. The probability of exiting the export market decreases with tenure and after the discovery stage is only 5% higher than the exit probability of well established exporters; the cutoff for exporting experiences 90% of its long-term adjustment over the same period; (iii) firms that continuously export over a period of six years observe a 137% increase in their (ex-ante) probability of serving the foreign market and a 900% increase in their (average) export premia, and (iv) temporary shocks to the profitability of serving the export market can have permanent consequences on aggregate trade volumes. In particular, export promotion policies that temporarily subsidize the fixed costs of maintaining a presence in the foreign market can result in permanent increases in aggregate trade volumes. The impact of these types of policies crucially depends on the speed at which firms are able to uncover their export profitability.


This paper develops a multi-country, general equilibrium, semi endogenous growth model of innovation and trade in which specialization in innovation and production are jointly determined. The new distinctive element of the model is the ability of the agents to direct their research efforts to specific classes of goods, in a context of heterogeneous innovation capabilities across countries and contemporaneous decreasing returns to R&D. The model features a two-way relationship between trade and technology absent in standard Ricardian trade models. I calibrate the model using a sample of 29 countries and 18 manufacturing industries and quantify the importance of endogenous adjustment sin technology. I find that endogenous adjustments in technology due to directed research can account for up to 52.8% of the observed variance in comparative advantage in production. In addition, the model suggests that standard Ricardian models overestimate the welfare losses from increases in trade costs and underestimate the welfare gains of trade liberalizations.