A simulation is an approximate imitation of the operation of a process or system; that represents its operation over time. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games. A simulation is an approximate imitation of the operation of a process or system; that represents its operation over time. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games. A simulation is an animated model that mimics the operation of an existing or proposed system, like the day-to-day operation of a bank, running an assembly line, or assigning staff in a hospital or call center. Simulation offers a powerful, evidence-based approach to decision making - by using a virtual representation to test the impact of process changes and 'what if' scenarios, you can find an approach that delivers the best results.