Unity of command means that no employee should be subject to orders of more than one immediate superior. If he is, he might receive conflicting orders from them and his position may become an impossible one.
Diversity of command may also result in the subordinates playing off one superior against another or others. All this may cause confusion and blurring of responsibility.
Although on theoretical grounds the soundness of the principle of unity of command appears unassailable, in practice we find important exceptions to it.
Thus, an individual employee is frequently subject to a dual command or control – one administrative and the other technical or professional. Take for example, the case of a medical officer of health in one our local bodies.
Administratively he is under the Chairman of the local body, but professionally under the state Director of Public Health.
The reasons for this kind of arrangement is the difficulty in finding supervisory officers qualified and competent to exercise administrative as well as technical control . It is difficult to expertise in more than one matter.
Perhaps a better argument in favour of the principle of Unity of Command would be to say that its violation does not really occur when an employee receives orders from more than one superior in respect of different matters or aspects of matters under his charge.
It is violated only when a man receives orders from more than one superior in the same matter.