Unbalanced hierarchy
The branches in an unbalanced hierarchy descend to different levels.
For example, in the following diagram, the highest level in an organization is the CEO (Level 1); Level 2 is the vice-presidents and the CEO's executive assistant. The executive assistant does not have subordinates, unlike the vice-presidents.

An unbalanced hierarchy can also be ragged. In a ragged-unbalanced hierarchy, there are gaps in the levels and the levels descend to different depths.