ABSTRACT
This chapter provides an overview of methods used for modeling HIV in human populations. Because of the chronic nature of HIV and the strong behavioral aspect associated with its spread, understanding and controlling HIV spread is complex. Two behavior-related HIV transmission pathways are most prominent: unprotected sexual contact and sharing injecting equipment. Modeling is needed and is broadly used to forecast potential behavior outcomes and specific intervention impacts because natural experiments can be too long, costly, unethical, and often impossible to conduct. The need for modeling goes beyond long-term forecasting at the population level. Modeling takes many forms, including mental and statistical models, system dynamics (SD), and microsimulations, and thus can be confusing. A number of approaches and methods have been used in modeling HIV. SD models provide a flexible approach to modeling population processes. SD models can consider how history affects future transitions and feedback loops.
