System Dynamics (SD) is a methodology whereby complex, dynamics and nonlinear interactions in social systems can be understood and analyzed, and new structures and policies can be designed to improve the system behavior. Similarly we can say, System Dynamics (SD) is a complex scientific and technological activity, for which is epistemological and methodological analysis could suggest some new and interesting perspectives both to practitioners and theorists of system dynamics (SD) The System models to have the most realistic representational content possible. There is a great different between purely Correlation or Statistical models and System Dynamics (SD. The System Dynamics (SD) models also try to offer explanation and understanding, not only forecasting and control (Forrester, 1961).