Influence, attention and expertise dilute as they are spread, so reach is bought at the cost of depth.
Weinberg applied it to consulting and to management span. The quantity being spread is fixed, so the only question is how thin it may be spread before it stops doing anything. The uncomfortable implication is that the person with the widest remit may be having the least effect anywhere, while appearing to be everywhere.
In practice
- A director on nine committees has a view on all nine and changes nothing on any.
- A specialist asked to cover four teams gives each a quarter of the attention that made them worth having.