Venture Capital Data: Opportunities and Challenges. Josh Lerner, 2017, Book Chapter, “Start-ups and other entrepreneurial ventures make a significant contribution to the US economy, particularly in the tech sector, where they comprise some of the largest and most influential companies. Yet for every high-profile, high-growth company like Apple, Facebook, Microsoft, and Google, many more fail. This enormous heterogeneity poses conceptual and measurement challenges for economists concerned with understanding their precise impact on economic growth.Link