After testing the model and its solution the next step of the study is to establish control over the solution by proper feedback of the information on variables which deviated significantly. As soon as one or more of the controlled variables change significantly the solution goes out for control. In such a situation the model may accordingly be modified.

Implementation of the Final Results: Finally the tested results of the model are implemented to work. This would basically involve a careful explanation of the solution to be adopted and its relationship with the operating realities. This stage of operation research investigation is executed primarily through the co operation of both the operations research experts and those who are responsible for managing and operating the system.