Innovation, Reallocation, and Growth
The Harvard Law School Forum on Corporate Governance and Financial Regulation 2013-06-25
In our paper, Innovation, Reallocation, and Growth, which was recently made publicly available on SSRN, we build a micro-founded model of firm innovation and growth, enabling us an examination of the forces jointly driving innovation, productivity growth and reallocation. In the second part of our paper, we estimate the parameters of the model using simulated method of moments on detailed U.S. Census Bureau micro data on employment, output, R&D, and patenting during the 1987-1997 period.
Our model builds on the endogenous technological change literature. Incumbents and entrants invest in R&D in order to improve over (one of) a continuum of products. Successful innovation adds to the number of product lines in which the firm has the best-practice technology (and “creatively” destroys the lead of another firm in this product line). Incumbents also increase their productivity for non-R&D related reasons (i.e., without investing in R&D). Because operating a product line entails a fixed cost, firms may also decide to exit some of the product lines in which they have the best-practice technology if this technology has sufficiently low productivity relative to the equilibrium wage. Finally, firms have heterogeneous (high and low) types affecting their innovative capacity—their productivity in innovation. This heterogeneity introduces a selection effect as the composition of firms is endogenous, which will be both important in our estimation and central for understanding the implications of different policies. We assume that firm type changes over time and that low-type is an absorbing state (i.e., high-type firms can transition to low-type but not vice versa), which is important for accommodating the possibility of firms that have grown large over time but are no longer innovative.