Discussion papers

CPM-2018-210 - 26 September 2018

Discussion paper: Using agent-based modelling to inform policy – what could possibly go wrong?

By Bruce Edmonds and Lia ní Aodha. Critiques the “Engineering” paradigm for policy development, in particular the prospects for prediction. Suggests an alternative approach – Reflexive Possibilistic Modelling, which (along side participatory and open political approaches) could be a more productive direction. Goes with an oral presentation to MABS 2018 and ICES 2018.

by Bruce Edmonds and Lia ní Aodha


Scientific modelling can make things worse, as in the case of the North Atlantic Cod Fisheries Collapse. Some of these failures have been attributed to the simplicity of the models used compared to what they are trying to model. MultiAgent-Based Simulation (MABS) pushes the boundaries of what can be simulated, prompting many to assume that it can usefully inform policy, even in the face of complexity. That said, MABS also brings with it new difficulties and potential confusions. This paper surveys some of the pitfalls that can arise when MABS analysts try to do this. Researchers who claim (or imply) that MABS can reliably predict are criticised in particular. However, an alternative is suggested – that of using MABS for a kind of uncertainty analysis – identifying some of the possible ways a policy can go wrong (or indeed go right). A fisheries example is given. This alternative may widen, rather than narrow, the range of evidence and possibilities that are considered, which could enrich the policy-making process. We call this Reflexive Possibilistic Modelling.

Model is available at: http://comses.net/codebases/4204
Slides available at: http://slideshare.net/BruceEdmonds