Scientists, policymakers, and advocates are increasingly advised to use “the public health approach” to address myriad social issues, from alcoholism and arthritis to vision care and war. However, it is rarely clear what exactly is meant by “the public health approach.” Policymakers at the Centers for Disease Control and Prevention (CDC) describe the public health approach as a four-step model: Define the problem, identify risk and protective factors, develop and test prevention strategies, and ensure widespread adoption of effective programs. 1 Yet the public health approach is more than this model, for these steps are little more than a scientific approach to any problem. We believe that the public health approach has five key components. First, the approach is population-based and rarely involves identifiable individuals. Second, it focuses on prevention—usually as far upstream as possible. It is often more effective to change the agent and the environment in which the problem occurs than it is to focus on trying to change the individual with the last clear chance to prevent the problem (eg, victim or perpetrator). Third, borrowing from human-factors engineering, public health uses a systems approach—trying to create a system in which it is difficult (rather than easy) to make mistakes or behave inappropriately and in which mistakes and inappropriate behavior do not lead to serious injury. Fourth, the approach is broad and inclusive—it examines all possible interventions, including changing social norms and passing new laws, and it tries to engage as many people and institutions as possible in a multifaceted way. Finally, the approach tends to emphasize shared responsibility over blame. Prevention works best when everyone is trying to help. By contrast, assessing blame can sometimes be counterproductive to the goal, 2 which is to prevent the problem from occurring.

A great success of the 20th century—the reduction in motor vehicle deaths3—helps illustrate the public health approach. Almost all motor vehicle crashes and deaths can be ascribed to driver error or deliberate misbehavior (eg, speeding and running red lights). Drivers, especially when tired, drunk, or angry, sometimes make mistakes or behave inappropriately. At first blush, it would appear that if drivers are at fault for almost all collisions, the focus of prevention should be on drivers. Indeed, in the 1950s, the safety focus was on driver education and enforcement of the traffic laws. At the same time, public health physicians began asking a different question—not “Who caused the accident?” but “What caused the injury?” 4 They found that drivers’ vital organs were ruptured when the spearlike steering column punctured the chest; faces and major arteries were ripped apart by windshield glass; occupants were thrown from the car; and many motorists died when their car left the road and hit the unyielding signs, lights, and trees that lined highways. These physicians asked, Why can’t cars have collapsible, energy-absorbing steering columns, safety glass, seat belts, and air bags? Why can’t we make the roads safer? After all, we were not placing unyielding impediments along the sides of airport runways.