New research uses survey data from over 1,000 CEOs across six countries and the financial performance of their companies to answer questions about CEO effectiveness. The evidence suggests that hands-on managerial CEOs are, on average, less effective than leaders who stay more high-level. This distinction mirrors John Kotter’s distinction between leaders and managers. Leaders tend to be more prevalent in larger firms and in industries that are more skill-intensive and complex, while managers tend to run smaller and simpler organizations. But just as important is understanding and finding the right fit between the CEO’s leadership style and what the company actually needs.