Discrete Event Simulation for Health Technology Assessment

105Implementation

An interesting example of a special entity was implemented in a model

assessing various vaccination strategies to prevent bacterial meningitis epi-

demics (Caro etal. 2007). The validation work for that model showed that

the outbreaks of disease occurring in the simulation were less frequent than

those observed in available epidemiologic data, despite careful construction

of the risk equations. Rather than calibrating the equations to the new data, a

special event was incorporated that triggered a change in the force of infec-

tion, increasing the chance of an outbreak. The sole purpose of the special

Outbreak Demon entity was ...