Simulations can be created to recreate incredibly complex systems. However, applied games are best designed based on simulations that are "good enough". As long as the results of the simulation seem to match with reality most the time and the resulting game is deemed fun and educational, "good enough" is good enough.
Michael, D. & Chen, S., Serious Games: Games That Educate, Train and Inform, Course Technology Cengage Learning, 2006
Added by: Micah Hrehovcsik, Senior Lecturer / Game Design Researcher