Abstract
Public health asks of systems science, as it did of sociology 40 years ago, that it help us unravel the complexity of causal forces in our varied populations and the ecologically layered community and societal circumstances of public health practice. We seek a more evidence-based public health practice, but too much of our evidence comes from artificially controlled research that does not fit the realities of practice. What can we learn from our experience with sociology in the past that might guide us in drawing effectively on systems science?