Agent-based modelling

Agent-based models are used to describe and analyze complex systems populated by many heterogeneous and interacting units. These models rely on computer simulations to study their object of interest. Their specificity relies on the pivotal role of agents, here defined as any software entity that can affect the outcomes of a computationally constructed world. Although the ideas underlying ABMs can be traced back to the 1940s, this field began to thrive in the 1990s, when computational power became more diffuse. Nowadays, ABM models are employed to study a wide variety of social phenomena, ranging from sociology to history and economics. In all these fields, ABMs are increasingly appreciated for their ability to provide a microfoundation for collective phenomena and to serve as tools for counterfactual analysis and policy making.