Parkinson’s Law derived from C. N. Parkinson’s observations within the British Civil Service (of the then British Empire).
It postulates that the amount of workers in large organizations always grows, even if the work stays the same, because
- Prestige in hierarchies builds on (having) subordinates.
- Workers in bureaucracies tend to make work for other workers in the same system.
The inverse of this law is that the amount of work expands to fill the time available for completion, which adds complexity and therefore requires more work(ers).
Consequently determining the low-end of required people to fulfill a task cannot be derived from observation of their “business”.