Since there are multiple agents and sites in every iteration of the model, we need a way to summarize the properties of the agents and sites in order to understand the behavior of the overall system. We use the mean value for this. The mean outcome properties for agents and sites change over the iterations for 100 independent runs of the model, this is shown in SI Appendix, Fig. S5. When we further summarize each independent run of the model to investigate the effects of parameters on the outcomes we only consider the mean value in the final iteration of the model.