Answer:
Each manager should be evaluated on the costs but not the revenues that are under his or her control.
Step-by-step explanation:
Controllability refers to the amount of influence that a manager has over costs or revenues. In responsibility accounting, only those elements are identified which are controllable. A person is given the responsibility for managing such kind of elements.
A person is given an authority to control the costs so that they are able to keep up their performance.
However, according to the controllability concept to responsibility accounting,
each manager should also be evaluated on the revenues that are under his or her control.