We build a model of firm-level innovation, productivity growth and reallocation featuring endogenous entry and exit. A key feature is the selection between high- and low-type firms, which differ in terms of their innovative capacity. We estimate the parameters of the model using detailed US Census micro data on firm-level output, R&D and patenting. The model provides a good fit to the dynamics of firm entry and exit, output and R&D, and its implied elasticities are in the ballpark of a range of micro estimates. We find industrial policy subsidizing either the R&D or the continued operation of incumbents reduces growth and welfare. For example, a subsidy to incumbent R&D equivalent to 5% of GDP reduces welfare by about 1.5% because it deters entry of new high-type firms. On the contrary, substantial improvements (of the order of 5% improvement in welfare) are possible if the continued operation of incumbents is taxed while at the same time R&D by incumbents and new entrants is subsidized. This is because of a strong selection effect: R&D resources (skilled labor) are inefficiently used by low-type incumbent firms. Subsidies to incumbents encourage the survival and expansion of these firms at the expense of potential high-type entrants. We show that optimal policy encourages the exit of low-type firms and supports R&D by high-type incumbents and entry -- National Bureau of Economic Research web site.

We build a model of firm-level innovation, productivity growth and reallocation featuring endogenous entry and exit. A new and central economic force is the selection between highand low-type firms, which differ in terms of their innovative capacity. We estimate the parameters of the model using US Census micro data on firm-level output, R&D and patenting. The model provides a good fit to the dynamics of firm entry and exit, output and R&D. Taxing the continued operation of incumbents can lead to sizable gains (of the order of 1.4% improvement in welfare) by encouraging exit of less productive firms and freeing up skilled labor to be used for R&D by high-type incumbents. Subsidies to the R&D of incumbents do not achieve this objective because they encourage the survival and expansion of low-type firms.

The number of immigrants in the US science, technology, engineering, and mathematics (STEM) workforce and among recipients of advanced STEM degrees at US universities has increased in recent decades. In light of the current public debate about immigration, there is a need for evidence on the economic impacts of immigrants on the STEM workforce and on innovation. Using new data and state-of-the-art empirical methods, this volume examines various aspects of the relationships between immigration, innovation, and entrepreneurship, including the effects of changes in the number of immigrants and their skill composition on the rate of innovation; the relationship between high-skilled immigration and entrepreneurship; and the differences between immigrant and native entrepreneurs. It presents new evidence on the postgraduation migration patterns of STEM doctoral recipients, in particular the likelihood these graduates will return to their home country. This volume also examines the role of the US higher education system and of US visa policy in attracting foreign students for graduate study and retaining them after graduation.

This volume provides an understanding of firms' R&D and innovation strategies and their economy-wide consequences. It is based on the premise that differences in firm-level returns, as well as economy-wide outcomes, may be linked to the heterogeneous ways in which firms organize and undertake R&D and innovation activities. It emphasizes innovation strategies of innovating firms, and reflects that innovation efforts do not represent a uniform type of expenditure. Organized into three parts the volume moves from the micro to the macro-level. This structure highlights the notion that R&D and innovation and growth are two interdependent perspectives. The first of these is micro-oriented and focuses on innovation processes of firms, where R&D activities and other innovation efforts give rise to consequences such as a strengthening of resource bases, growth of sales and employment, patents, new products, increasing productivity and profits, and improved chances of survival. The second perspective comprises economy-wide effects in the form of overall technological change, growth in total factor productivity, and structural change processes, where certain sectors may benefit from new inputs from other sectors while others experience declining markets and reduced output. The book brings together contributions and perspectives from both economics and business scholars, and will appeal to academics, researchers, and students interested in R&D and innovation strategies, international business, business strategy, and the economics of technological change.

We use detailed product- and firm-level data to study the sources of innovation and the patterns of productivity growth over the period from 2007 to 2013. We document several new facts on product reallocation. First, every quarter around 8 percent of products are reallocated in the economy, and the entry and exit of products are prevalent among different types of firms. Second, most reallocation of products occurs within the boundaries of the firm. The entries and exits of firms only make a small contribution in the overall creation and destruction of products. Third, product reallocation is strongly pro-cyclical and declined by more than 25 percent during the Great Recession. This cyclical pattern is almost entirely explained by a decline in within firm reallocation. Motivated by these facts, we study the causes and consequences of reallocation within incumbent firms. As predicted by Schumpeterian growth theories, the rate of product reallocation strongly depends on the innovation efforts of the firms and has important implications for revenue growth, improvements in products' quality, and productivity dynamics. Our estimates suggest that the decline in product reallocation through these margins has contributed greatly to the slow growth experienced after the Great Recession.

Measuring Entrepreneurial Businesses: Current Knowledge and Challenges brings together and unprecedented group of economists, data providers, and data analysts to discuss research on the state of entrepreneurship and to address the challenges in understanding this dynamic part of the economy. Each chapter addresses the challenges of measuring entrepreneurship and how entrepreneurial firms contribute to economies and standards of living. The book also investigates heterogeneity in entrepreneurs, challenges experienced by entrepreneurs over time, and how much less we know than we think about entrepreneurship given data limitations. This volume will be a groundbreaking first serious look into entrepreneurship in the NBER's Income and Wealth series.