organizations engaged in injury prevention research and practice, and thereby began to build the infrastructure for a new field. For additional historical information, see the time line in Appendix B.
Modern injury science began to take shape as a distinct field in the mid-1960s. Perhaps the key conceptual development was the recognition that patterns of injury distribution and causation can be analyzed using the epidemiological tools of public health and that the etiology of injury includes environmental factors and interactions between human and environmental factors. The formulation of the prevailing scientific paradigm for studying the causes and prevention of injury is generally attributed to William Haddon, a public health physician. Building on the work of John Gordon (1949) and James Gibson (1961), Haddon (1968) observed that all injury events are attributable to the uncontrolled release of one of five forms of physical energy (kinetic, chemical, thermal, electrical, and radiation). From a preventive or ameliorative standpoint, interventions can be made during three temporal phases in relation to the injury event: (1) a pre-event phase, during which the energy becomes uncontrolled; (2) a brief event phase in which the uncontrolled energy is transferred to the individual, resulting in injury if the energy transfer exceeds the tolerance of the body to absorb it; and (3) a post-event phase, during which attempts can be made to restore homeostasis and repair the damage. This three-phase conceptualization of injury causation can be combined with the traditional public health categorization of risk factors and intervention opportunities—host (the potential injured person), agent (the energy and the vehicle through which it is transferred), and environment (both physical and social)—to create a 12-cell matrix that can be modified to apply to any circumstance of injury (Figure 1.2). Using this model to identify risk factors and potential interventions during all three temporal phases, Haddon summarized the range of interventions as follows: (1) preventing or limiting energy buildup; (2) controlling the circumstances of energy use to prevent uncontrolled release; (3) modifying the energy transfer phase to limit damage; and (4) improving emergency response, treatment, and rehabilitative care to limit disability and promote recovery.