We present a general equilibrium model of the response of firms' decisions to operate, innovate, and engage in international trade to a change in the marginal cost of international trade. We find that, although a change in trade costs can have a substantial impact on heterogeneous firms' exit,...

We examine the quantitative impact of policy-induced changes in innovative investment by firms on growth in aggregate productivity and output in a model that nests several of the canonical models in the literature. We isolate two statistics, the impact elasticity of aggregate productivity growth...

We study a market with free entry and exit of firms who can produce high-quality output by making a costly but efficient initial unobservable investment. If no learning about this investment occurs, an extreme "lemons problem" develops, no firm invests, and the market shuts down. Learning...

"We present a tractable model of innovating firms and the aggregate economy that we use to assess the link between the responses of firms to changes in innovation policy and the impact of those policy changes on aggregate output and welfare. We argue that the key theoretical determinant of the...

We present a general equilibrium model of the decisions of firms to innovate and to engage in international trade. We use the model to analyze the impact of a reduction in international trade costs on firms' process and product innovative activity. We first show analytically that if all firms...