How Much Managers Affect Productivity

It's a cliché for organizations to say that their people are their most important asset, but how important is the person at the top? Can we measure the impact of a CEO or a manager? Chicago Booth's Mike Gibbs gives us a survey of economic research on leadership and management. How much of a difference does a good leader make? And why do "manager-types" so often struggle when they get promoted to leadership roles?