System Model
How to Run
Click the link above to download the system model. To open the system model, you will need the VensimPLE application downloaded on your computer. You will then be able to view and run the model. To run the model, press "Simulate". To adjust parameters, press "SyntheSim" and adjust the slider bars.
Screenshots
Model Diagram
Model with Low Vaccination Rate
Model with High Vaccination Rate
Model with High Vaccination Rate and Vaccines are 100% effective
Observations
When running the model with a low vaccination rate, the number of sick people greatly increased, and only a few people were able to get vaccinated before the disease outbreaks. The number of deaths steadily rose until most of the people were dead. In the model with a higher vaccination rate, you can see the number of vaccinated people jumped quickly, and then leveled off. In the model where vaccines were 100% effective, the number of vaccinated people steadily rose until everyone was either cured and vaccinated or dead.
In all three of these models, you don't see the effects of herd immunity because it assumes everyone comes in contact with everyone else. Therefore, everyone either eventually becomes dead or vaccinated. Another thing I noticed when playing around with the system model is that sometimes an extremely high death rate results in a lower total amount of deaths than a somewhat high death rate. This is because people with the disease will die out before they can spread the disease to everyone else. As far as scale goes, nothing changes if you change the amount of people because everything is dealing with percentages. The only change is that larger models take more time to calculate. I tried raising the number of people to an obscenely large number, and eventually Vensim crashed because it couldn't handle so many calculations.