An agent-based model of the 2020 international policy diffusion in response to the COVID-19 pandemic with particle filter

Global problems, such as pandemics and climate change, require rapid international coordination. One notable example was the imposition of ‘lockdown’ policies in response to the COVID-19 pandemic in early 2020. Here we build an agent-based model of this rapid policy diffusion, where countries constitute agents and with the mechanism for diffusion being peer mimicry. We utilize data assimilation to constrain the model against observations in ‘real-time’. We find that the model is able to predict the policy diffusion relatively well and that the data assimilation improves the fit to the data.