What Data is Needed? 

In order to determine the parameters for our modified SI model, we needed a data set to run the model against to allow us to optimize our key parameters. The parameters that we were interested in determining were our infectivity parameter, our birth rate, and our two death rates from the susceptible and infected states, respectively. Clearly, in order to determine the correct parameters, it was important to find an accurate and complete data set that would show the HIV infected population and susceptible population over time.

Infected Population Data

We utilized data from the CDC which recorded the HIV infected population in the United States from 1981 to 1998. We determined this would be good data to use since it was from when HIV was known but before ART treatment was fully introduced. We hoped this would give us a realistic picture of the infectivity of this disease. 

Susceptible Population Data

We decided that since HIV is a Sexually Transmitted Infection, the entire United States population is not representative of the susceptible population. Therefore, we focused on the most sexually active United States population, people between the ages of 20-49, during the same time period of the infected disease data.