Confidence that something can be done rises sharply with distance from having to do it.
The observation names a real asymmetry in organisations: the person specifying the work bears none of its discovered difficulty, so the estimate is formed without the information that would correct it. It explains why plans get more ambitious as they move up a hierarchy and why the correction only arrives at the level that must execute.
In practice
- A deadline set two levels above the people doing the work is set by the person with least access to how long it takes.
- A committee that has never used the system specifies its replacement in an afternoon.