The role of the manager in promoting production is a little-understood phenomenon. In particular, it is difficult to separate managers’ contributions from the abilities of the workers they supervise. Firms may therefore mistakenly attribute the contributions of the workers to the managers who happen to oversee them. With its plethora of performance data, the National Basketball Association (NBA) provides a natural setting to measure the contribution of a head coach to the performance of his team. We find that some highly regarded coaches deserve their accolades, but several coaches owe their success to managing highly talented teams. Conversely, some coaches with mediocre records have made significant contributions to the performance of their players. Most coaches, however, do not have a statistically significant impact on their players or their teams, making them nothing more than the “principal clerks” that Adam Smith called managers over 200 years ago.