2021-10-19 09:19:19

How do we do science?

How do we get data?

Experimental studies

  • The approach used in almost all bench/lab sciences.
  • Clinical trials in Public Health and Medicine.
  • Potentially most powerful because we have most control.
  • Not always possible.
https://www.smbc-comics.com/

https://www.smbc-comics.com/

Observational studies

  • Widely used in Public Health and other areas (e.g., Sociology, Psychology, Economics, Geology).
  • Not as powerful as experimental studies.
  • Often the only option.
Jim Borgman

Jim Borgman

Simulation/modeling studies

  • Computer models can represent a real system.
  • Simulated data is not as good as real data.
  • Often the only option.
https://xkcd.com/

https://xkcd.com/

Modeling definition

  • The term modeling usually means (in science) the description and analysis of a system using mathematical or computational models.
  • Many different types of modeling approaches exist. Simulation models are one type (with many subtypes).
Not this

Not this

This one

This one

Simulation models

Computer models for some scenario (e.g. the spread of flu or COVID in the US) to understand what is going on, to make forecasts and to evaluate the impact of different interventions.

Germann et al 2006 PNAS

Germann et al 2006 PNAS

Simulation modeling areas

Source: NOAA

Source: NOAA

  • Weather forecasting.
  • Simulations of man-made, engineered system.
  • Predicting the economy.
  • Infectious disease transmission.

Simulation modeling overview

  • Build a model that simulates the process of disease transmission. Include any details that are relevant for the question, omit everything else.
NY Times

NY Times

Using models I

Using models I

Using models II

Learning simulation modeling - challenges

  • It takes time to learn how to build, use and interpret models.
  • One generally needs to write code to build simulation models.
Markus Spiske on Unsplash

Markus Spiske on Unsplash

Learning simulation modeling - a solution

DSAIDE - Dynamical Systems Approach to Infectious Disease Epidemiology

  • Software that can teach uses of simulation modeling.
  • Does not require any coding.
  • Allows for active/hands-on learning.
https://ahgroup.github.io/DSAIDE/

https://ahgroup.github.io/DSAIDE/

Exploring DSAIDE

  • We’ll look at the most basic model for population level infectious disease modeling.
  • This model tracks individuals (humans or animals) in 3 states, susceptible, infected/infectious and recovered/removed. It is called the SIR model.

\[ \begin{aligned} \dot S & = -bSI \\ \dot I & = bSI - gI \\ \dot R & = gI \\ \end{aligned} \]

Try for yourself

Summary