Topic

Dynamic transmission and system dynamics models

Dynamic models let the risk of infection change with the number of people already infected, which static models cannot do. Compartmental models such as the SIR and SEIR models capture the indirect protection that vaccination gives to unvaccinated people. System dynamics models apply the same stock and flow logic to health services.

Concepts in this topic

• Compartmental ModelA compartmental model represents a population as quantities in mutually defined states and describes how people or other units flow between those states over time.
• Dynamic ModelA model representing how a system's variables change over time in response to feedback and interaction among components, unlike a static model.
• Dynamic Transmission ModelA dynamic transmission model represents how an infectious disease spreads through a population while the risk of infection changes with the number and characteristics of infectious people.
• SEIR ModelAn extension of the basic epidemic model adding an exposed compartment for individuals infected but not yet infectious, before they become infectious.
• SIR ModelA basic epidemic model dividing a population into susceptible, infectious, and recovered compartments, representing flow between them using differential equations.
• Stock and Flow ModelA system dynamics structure representing accumulations, called stocks, such as infected individuals, and the rates of change into and out of them, called flows.
• System Dynamics ModelA modelling approach representing a complex system using stocks, flows, and feedback loops to capture how it evolves through internal dynamics.
• Transmission ModelA model explicitly representing how an infectious disease spreads through a population by tracking interaction between infectious and susceptible individuals.