What is Model Simulation?
model is a simplified mathematical, logical, or other
structured representation of a system that approximates
the real system. Models are simpler than the system they
represent but should incorporate most of its relevant
features. Models are created with data, equations, and
computations to imitate the behavior of the system. A
key advantage of working with models is that they can be
reconfigured and experimented with, while this could be
expensive, time-prohibitive, impractical, or unethical
to do in the actual system.
purpose of a model is to enable users to predict how
changes to the system will affect its outputs.
In public health, a model can be a useful tool to
complement traditional public health methods in policy
planning, assessment, and evaluation. For instance,
evaluation of the data collected by public health
programs result in estimates of short-term impacts on
the individuals and institutions directly targeted by
these programs. Simulation models can complement these
analyses by combining the results from the short-term
evaluations with data and evidence from existing studies
to project long-term outcomes and for a wider
Simulation models could also generate projections of
outcomes under a variety of scenarios by combining
interventions, changing time frames of the intervention,
or targeting different populations. For example, a model
could help compare the impact an intervention would have if it
targeted only underserved populations or the entire
population of Los Angeles.
Additionally, simulation models can be designed
to capture the competing risks that may arise from
interventions or policy changes, so that policymakers
have a more realistic estimate of the impact of the
interventions by taking into account the trade-offs
between the costs and benefits of the various
What are the basic components of a Model?
While different modeling methods have different basic
components, all simulation models have inputs, outputs,
and the model itself.
example, below we show the inputs and outputs in the
Future Los Angeles simulation model, one of our current
modeling projects, which will provide long-term
projections of health and economic outcomes for the
population of Los Angeles County (LAC).
Another example is shown below. This diagram represents the
transitions over time between four health states
(uninfected, latent TB infection, TB disease, and
death). This model was used to estimate the health and
economic impact of four alternative policies to screen
school-aged children in Los Angeles County for
Where can I learn more about simulation modeling?
For more information about where you can learn more
about simulation modeling , see External