Agent-based models typically involve large numbers of interacting individuals with widely differing characteristics, rules of behavior, and sources of information. The dynamics of such systems can be extremely complex due to their high dimensionality. This chapter discusses a general method for rigorously analyzing the long-run behavior of such systems using the theory of large deviations in Markov chains. The theory highlights certain qualitative features that distinguish agent-based models from more conventional types of equilibrium analysis. Among these distinguishing features are: local conformity versus global diversity, punctuated equilibrium, and the persistence of particular states in the presence of random shocks. These ideas are illustrated through a variety of examples, including competition between technologies, models of sorting and segregation, and the evolution of contractual customs.
"I think the power of #MeToo is how it reveals the overwhelming scope and breadth of these problems, and how they affect victims. It forced individuals to recognize that there are structural features to what’s happening, and thus that everyone has a role to play in preventing assault and harassment.”