Charles Eesley's research focuses on the influence of the external environment on entrepreneurship. Specifically, he investigates the types of environments that encourage the founding of high growth, technology-based firms. Although he builds on previous literature that explains why entrepreneurs are successful on the basis of individual characteristics, network ties, and strategy, Eesley's major contribution is to demonstrate that institutions matter. He shows that effective institutional change influences who starts firms, not just how many firms are started. Studying the implications of institutional change for entrepreneurship is difficult because it requires that institutions vary while other aspects of the environment remain constant. Thus, Eesley has repeatedly studied entrepreneurship in a single country (China, Japan, and the U.S.) before and after a major institutional change that has intentionally or unintentionally altered the landscape for people who seek to found new firms. His research is divided into three streams: (1) how formal institutions (policies, legal structures and regulations) influence entrepreneurship, (2) how informal institutions (accepted practices and norms) shape entrepreneurial opportunities, and (3) how the environments of particular industries influence the success of entrepreneurial teams.