An entity which can take a role; a function, service, or identity. Müller (2007) Area 39, 2 calls the geographer ‘an active agent who moulds the production of meaning’. Bondi (2005) Antipode 37, 3 holds that neoliberalism envisages people as autonomous, individualized, self-directing, decision-making agents. ‘Interdependencies between agents are constrained by social and spatial structure, but, over time, structure and agency are mutually constituted’ (Plummer and Sheppard (2006) J. Econ. Geog. 6). The term ‘agent-based model’ refers to ‘a broad class of computational models known also as “multi-agent models”. As the name suggests, the model consists of a number of different “agents” that represent real-world entities such as households, businesses, individuals, and so forth. Each agent follows a set of relatively simple rules (an algorithm) controlling its interactions with other adjacent agents and its immediate environment over time’ (Green (2013) TIBG 38, 1, 2).