Span of Control

Span of control: a definition

Span of control (نطاق الإشراف), also called span of management, is the number of subordinates whom one manager supervises directly. The word directly sets the limit of the count. It covers the people who report straight to that manager, and not the people who report to those subordinates further down the line.

In Arabic the term has a second name, نطاق التحكم, which is a literal rendering of span of control. Both names refer to the same count.

Span of control is a number, and it is a number with a direct bearing on the shape of the organisational structure. Once the span is known for each manager, the number of managers needed at each level follows from it, and so does the number of management layers that stand between the top of the organisation and the people who carry out the work.

How span of control shapes the organisational structure

A span of control is described as wide or narrow according to the number of subordinates that each manager supervises directly, and each of the two gives the structure a different shape:

• A wide span. It means a large number of subordinates for each manager. It produces a flat structure with fewer management layers. Decisions are faster, because a decision passes through fewer levels between the person who takes a decision and the people it concerns, but the supervision that each individual receives is lighter, since one manager supervises more people.
• A narrow span. It means a small number of subordinates for each manager. It produces a hierarchical structure with more management layers. Each individual is followed up more closely, since one manager supervises fewer people, but a decision is slower to travel from the top of the structure to the bottom, because it passes through more levels on the way.

An example of the effect of span of control

Take an establishment with 100 front line employees, meaning staff who carry out the work and supervise no one. The 100 employees and their work are the same in both cases below, and only the span changes. The employees themselves are not counted as a management layer. Each layer of managers is counted by dividing the number of people in the layer below it by the span, and the division is repeated until a single manager is left at the top:

• With a span of control of 10. The 100 employees need 10 managers, one for every 10 of them. Those 10 managers then need one manager above them. The result is two management layers.
• With a span of control of 4. The 100 employees need 25 management posts, one for every 4 of them. Those 25 managers then need about 6 more above them, and those in turn need someone to manage them. The result is three management layers or more, and a much higher management wage bill than with a span of 10.

The figure of about 6 at the second layer is rounded. Divided by 4, 25 managers give 6.25, so if no manager at the second layer takes more than 4 subordinates, that layer needs 7. Whether the second layer has 6 managers or 7, at a span of 4 they need 2 managers above them, and those 2 need one more, which brings the count to four management layers. That count falls within the three layers or more stated for this span. On the same strict count, a span of 4 needs 35 managers in all (25, 7, 2 and 1), against 11 (10 and 1) for a span of 10.

The difference between the two spans is not an organisational detail. It amounts to fifteen additional managers in the first management layer alone, 25 against 10, and a whole layer of decision above them. Each of those additional managers is a post that carries a wage, which is where the higher management wage bill comes from. Each additional layer is one more level through which a decision passes on its way from the top of the structure to the bottom.

What determines an appropriate span of control

No span of control is correct in absolute terms, so the definition fixes no figure that every manager should supervise. The span that suits a team depends on factors that narrow it or widen it, and these are the factors:

• Similarity of tasks. It is the degree to which the work of the team members is alike. A team whose members do similar work can be supervised with a wider span than a team in which each member works in a different specialism, where the manager oversees as many kinds of work as there are members.
• Experience of the team. It concerns how experienced the members of the team are in the work they do. A seasoned team can bear a wider span than a team whose members are new to the work.
• Geographical spread. It is the distance between the places in which the members of the team work, such as the branches of one establishment. Branches that are far apart from one another narrow the span, compared with a team that works in one place.
• Risk of error. It reflects what a mistake in the work costs the establishment. Work in which an error is costly calls for closer supervision, and closer supervision is what a narrow span provides.

How span of control differs from the organisational structure

The organisational structure describes who reports to whom. Span of control measures how many people report to each of them, counted for each manager separately.

The first is a map, and the second is the number that determines how many layers that map needs in the first place. The map shows the reporting lines between positions. The span of control gives the number of lines that run to each manager, and from that number, applied to the people at the bottom of the structure, comes the number of layers the map has.

This is an explanation of the concept, not legal advice.