What is management by objective? How it evaluates the performance by employees in organisation?

Management by objectives is a process of determining the essential objectives within an organisation so that all employees understand what is required of them in the organisation. The process also measures the employee's actual performance against the set standards.

Management by objective is one of the advanced forms of management where focus is on achievement of specific objectives, not the time spent on them, and not the effort spent in trying to achieve them.