Span of control, or the number of workers supervised directly, was a
second principle. In subdividing from the top downward, each work unit
had to be supervised and coordinated with other units, and the span of control
considered to be most effective was 5 to 10 subordinates. This rule of
thumb is still widely used in building administrative organizations. A single
executive, with power and authority flowing uniformly from the top to the
bottom, heads the pyramid-shaped structures stemming from this second
principle.