Span of control refers to the number of subordinates over whom a supervisor has direct control. In an organization, a manager is limited by time as well as by personal skills and cannot supervise an infinite number of persons.
Optimum span of control that which is neither too narrow nor broad. Organizations should aim at having an optimum number of subordinates to be supervised by one person. An ideal or optimum span of control is one which leads to efficient utilization of managers and effective performance of their subordinates. Too wide a span may mean that managers are receiving too little guidance or control. Too narrow may mean managers are under utilized. The number of subordinates a manager can supervise will depend on a number of factors and cannot be identified in advance.