Span of control (also referred to as Span of Management) refers to the number of employees who report to one manager. It is the number of direct reporters that a manager has and whose results he is accountable for.
Span of control is critical in understanding organizational design and the group dynamics operating within an organization. Span of control may change from one department to another within the same organization.
The span may be wide or narrow. A wide span of control exists when a manager has a large number of employees reporting to him. Such a structure provides more autonomy. A narrow span of control exists when the number of direct reportees that a manager has is small. Narrow spans allow managers to have more time with direct reports, and they tend to spark professional growth and advancement.