One of the questions frequently asked by system dynamics rookies is whether system dynamics is a form of discrete time (e.g., difference equation) modeling or continuous time (e.g., differential equation) modeling. The answer is that system dynamics is a continuous time modeling technique. In order to generate simulated solutions to their models, however, they employ discrete time approximations (i.e., DT is not infinitesimally small) to the underlying continuous time system. The discrete step simulation process is merely a tool used to approximate the true continuous time system.