Management involves coordinating and overseeing the work of other people so organizational goals can be accomplished efficiently and effectively. There are three levels of managers: first-line managers who oversee non-managerial employees, middle managers who oversee first-line managers, and top managers who make organization-wide decisions. Managers perform four core functions: planning, organizing, leading, and controlling. They also take on roles like leader, liaison, and monitor. While management has aspects of both an art and science, it is increasingly being viewed as a science as managers rely more on data and experimentation.