What is the more empowered person in the company to evaluate the effectiveness of the manager to achieve the strategic objectives and how?

I fully agree with the answers been added by EXPERTS................Thanks.

The strategic plan document should specify who is responsible for the overall implementation of the plan, and also who is responsible for achieving each goal and objective.

The document should also specify who is responsible to monitor the implementation of the plan and make decisions based on the results. For example, the board might expect the chief executive to regularly report to the full board about the status of implementation, including progress toward each of the overall strategic goals. In turn, the chief executive might expect regular status reports from middle managers regarding the status toward their achieving the goals and objectives assigned to them.