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.

We study how external versus internal innovations promote economic growth through a tractable endogenous growth framework with multiple innovation sizes, multi-product firms, and entry/exit. Firms invest in external R&D to acquire new product lines and in internal R&D to improve their existing product lines. A baseline model derives the theoretical implications of weaker scaling for external R&D versus internal R&D, and the resulting predictions align with observed empirical regularities for innovative firms. Quantifying a generalized model for the recent U.S. economy using matched Census Bureau and patent data, we observe a modest departure for external R&D from perfect scaling frameworks.

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.

Vollrath challenges our long-held assumption that growth is the best indicator of an economy’s health. Most economists would agree that a thriving economy is synonymous with GDP growth. The more we produce and consume, the higher our living standard and the more resources available to the public. This means that our current era, in which growth has slowed substantially from its postwar highs, has raised alarm bells. But should it? Is growth actually the best way to measure economic success—and does our slowdown indicate economic problems? The counterintuitive answer Dietrich Vollrath offers is: No. Looking at the same facts as other economists, he offers a radically different interpretation. Rather than a sign of economic failure, he argues, our current slowdown is, in fact, a sign of our widespread economic success. Our powerful economy has already supplied so much of the necessary stuff of modern life, brought us so much comfort, security, and luxury, that we have turned to new forms of production and consumption that increase our well-being but do not contribute to growth in GDP. In Fully Grown, Vollrath offers a powerful case to support that argument. He explores a number of important trends in the US economy: including a decrease in the number of workers relative to the population, a shift from a goods-driven economy to a services-driven one, and a decline in geographic mobility. In each case, he shows how their economic effects could be read as a sign of success, even though they each act as a brake of GDP growth. He also reveals what growth measurement can and cannot tell us—which factors are rightly correlated with economic success, which tell us nothing about significant changes in the economy, and which fall into a conspicuously gray area. Sure to be controversial, Fully Grown will reset the terms of economic debate and help us think anew about what a successful economy looks like.