Replicating complex agent based models, a formidable task

Authored by Elizabeth Donkin, Peter Dennis, Andrey Ustalakov, John Warren, Amanda Clare

Date Published: 2017

DOI: 10.1016/j.envsoft.2017.01.020

Sponsors: Biotechnology and Biological Sciences Research Council (BBSRC)

Platforms: Repast NetLogo

Model Documentation: ODD Flow charts

Model Code URLs: https://github.com/lizzydonkin/plantInsectPolyculture https://github.com/lizzydonkin/plantInsectPolycultureNetLogo

Abstract

Promoting replication of models is unarguably a positive step for agent based modelling, as replication promotes rigorous testing. Model replication remains rare, yet is vital to assessing the repeatability of existing agent based models. Notably, more work is needed to assess cross platform and language replication, which represent potential sources of variability between model results. An existing, complex agent based model was replicated using two widely used platforms (NetLogo and Repast). When results generated by the models were compared, the findings differed not only in magnitude but the trends produced by the data, resulting in different conclusions being drawn from each set of model predictions. The variation between the models is believed to be a result of the complexity of encoding a substantial theoretical model in particular programming languages. This highlights the express need to document replication of existing models in order to fully understand the potential limitations to replication. (C) 2017 The Authors. Published by Elsevier Ltd.

Tags

Agent-based model Individual-based model NetLogo ecology Model replication systems Repast Protocol Open code Code