We develop a model of firm learning in volatile markets with noisy signals and test its predictions using historical German data. Firms' forecasts improve with age. We exploit German Reunification as a natural experiment where firms in the East are treated with ignorance about the distribution...

We examine the quantitative predictions of heterogeneous firm models à la Melitz (2003) in the context of the Canada - US Free Trade Agreement (CUSFTA) of 1989. We compute predicted increases in trade flows and measured productivity across a range of standard models and compare them to the...