(often through causal feedback processes), while also studying the impact on the behavior of the system as a whole over time” (http://obssr.od.nih.gov/scientific_areas/methodology/systems_science/index.aspx).
Value of an intervention is defined as its benefits minus its harms and costs.
IOM (Institute of Medicine). 2003. Who will keep the public healthy? Washington, DC: The National Academies Press.
Kindig, D. A., and G. Stoddart. 2003. What is population health? American Journal of Public Health 93:366-369.