Commentary: individual risk prediction, individual risk, and population risk.

Provides a background to efforts aimed at impacting developmental outcomes across society and discusses challenges and consequences resulting from such efforts. Child and adolescent clinical psychology studies health and behavior with a focus on individuals. This may or may not present an accurate picture of factors relating to the overall levels of health and behavior in a population. In contrast, epidemiology typically studies health and behavior with a focus on populations. Differences between the clinical and epidemiological approaches are most apparent when promoting policy aimed at preventing future disorders or reoccurrence of disorders in at-risk individuals. Awareness of these issues may help clinical psychologists in efforts to inform or shape public policy.