Span of control is the term now used more commonly in business management, particularly human resource management. Span of control refers to the number of subordinates a supervisor has.
In simple words, span of control means the manageable number of subordinates of a superior. In the hierarchical business organization of some time in the past it was not uncommon to see average spans of 1-to-4 or even less. That is, one manager supervised four employees on average. In the 1980s corporate leaders flattened many organizational structures causing average spans to move closer to 1-to-10. That was made possible primarily by the development of inexpensive information technology. As information technology was developed capable of easing many middle manager tasks – tasks like collecting, manipulating and presenting operational information – upper managers found they could hire fewer middle managers to do more work managing more subordinates for less money.
The current shift to self-directed cross-functional teams and other forms of non-hierarchical structures, have made the concept of span of control less important.
Theories about the optimum span of control go back to V. A. Graicunas. In 1933 he used assumptions about mental capacity and attention span to develop a set of practical heuristics. Lyndall Urwick (1956) developed a theory based on geographical dispersion and the need for face to face meetings. In spite of numerous attempts since then, no convincing theories have been presented. This is because the optimum span of control depends on numerous variables including organizational structure, available technology, the functions being performed, and the competencies of the manager as well as staff. An alternative view is proposed by Elliott Jaques (1988) that a manager may have up to as many immediate subordinates that they can know personally in the sense that they can assess personal effectiveness.