Simulation, from the Latin simulare, means to "fake" or to "replicate." The Concise Oxford Dictionary of Current English defines simulation as a "means to imitate conditions of (situation etc.) with a model, for convenience or training." Sheldon Ross of the University of California, Berkeley, states less formally that "computer simulations let us analyze complicated systems that can't be analyzed mathematically. With an accurate computer model we can make changes and see how they affect a system." Simulation involves designing and building a model of a system and carrying out experiments to determine how the real system works, how the system can be improved, and how future changes will affect the system (called "what if" scenarios). Computer simulations of systems are effective when performing actual experimentation is expensive, dangerous, or impossible.

One of the principal benefits of using simulation to model a real-world system is that someone can begin...