Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
In a dynamic model with sunk export costs, a firm's export investment is lower under trade policy uncertainty, and credible preferential trade agreements (PTAs) increase trade even if current tariffs are low. Exploring Portugal's accession to the European Community as a policy uncertainty shock we find that the trade reform accounted for a large fraction of Portuguese exporting firms' entry and sales; the accession removed uncertainty about future EC trade policies; and this uncertainty channel accounted for a large fraction of the predicted growth. Our approach can be applied to other PTAs and sources of policy uncertainty. (JEL D22, F12, F14, F15, G31, L11)