Modeling the Spread of Acute Infection through a Population


These two models are based on an example in John Sterman's book "Business Dynamics". They simulate the spread of an acute infection through a population. It is assumed that one infected person enters a community of 10,000 people. The infection is never fatal (everyone recovers), and once you have been infected, you are immune from reinfection.

One model (continuous) assumes that the population is a continuous entity and thus you will find fractional population values (e.g., 2.44 people). Such a model is a good approximation of the system as long as the population size remains large. The other model (discrete) deals with the population as a collection of discrete entities. The rate of infection and the rate of recovery are given by the same equations; however population is moved to different states discretely according to the rates of infection and recovery. Therefore the results of this model are integer values and the model is also scalable to any smaller population size. View element notes and descriptions to view key model assumptions. Be sure to enter the dashboards to play around with the models. You can change three key input parameters that control the spread of the infection using the sliders.


Making Better Decisions In An Uncertain World