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.

The spillovers in knowledge among largely college-educated workers were among the key reasons for the impressive degree of economic growth and spread of entrepreneurship in the United States during the 1990s. Prior 'industrial policies' in the 1970s and 1980s did not advance growth because these were based on outmoded large manufacturing models. Zoltan Acs and Catherine Armington use a knowledge spillover theory of entrepreneurship to explain new firm formation rates in regional economies during the 1990s period and beyond. The fastest-growing regions are those that have the highest rates of new firm formation, and which are not dominated by large businesses. The authors of this text also find support for the thesis that knowledge spillovers move across industries and are not confined within a single industry. As a result, they suggest, regional policies to encourage and sustain growth should focus on entrepreneurship among other factors.

This book addresses the rising productivity gap between the global frontier and other firms, and identifies a number of structural impediments constraining business start-ups, knowledge diffusion and resource allocation (such as barriers to up-scaling and relatively high rates of skill mismatch).

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.

We analyze the impact of rising import competition from China on U.S. innovative activities. Using Compustat data, we find that import competition induces R&D expenditures to be reallocated towards more productive and more profitable firms within each industry. Such reallocation effect has the potential to offset the average drop in firm-level R&D identified in the previous literature. Indeed, our quantitative analysis shows no adverse impact of import competition on aggregate R&D expenditures. Taking the analysis beyond manufacturing, we find that import competition has led to reallocation of researchers towards booming service industries, including business and repairs, personal services, and financial services.