Span of Control is a term that describes the number of subordinate workers / organizational units under a single manager. Determination of span of control is one of the results of organizing and it is de-facto manifestation of formal organizational structure.
What is span of control for?
The reason for determining the span of control is the need for division of labor and natural limitations of the manager to manage certain number of people so that the procedure could be effective. There is no universally applicable rule for determining the number of people in a range of manager - it depends on many factors, from the complexity of the activities carried out by subordinates, frequency of mutual contacts, their character and skills of the manager. Recommended span of control varies between 5 to 10 subordinates and in some cases may be even greater. The manager should have with each subordinate clear relationship, and should also have an overview of the relationships within the social network of his subordinates.
Determination of span of control leads to creation of management levels (organizational levels) within the organizational structure. According to the width and number of levels the organizational structures are divided into tall (steep) and flat - see typology of organizational structure.