Safety may also increase, but by less than if there had been no behavioral response. When safety changes are largely invisible to the user, there is no evidence of any measurable human behavioral feedback. Likewise, when measures affect only the outcome of crashes, rather than their probability, no user responses have been measured." Lund and O'Neill (1986) reached similar conclusions. These conclusions based on studies involving motor vehicles are likely to apply to other injury areas (e.g., falls, firearms) when changes in products or the environment alter perceived risks, but relevant studies are not available. One area that has received attention is child-resistant packaging. Concern was expressed that child-resistant packaging would not decrease poisonings because, for example, parents would be prone to leave the bottles more accessible to children (Viscusi, 1984), but there is definitive evidence that child-resistant packaging does reduce child poisonings (Rodgers, 1996). Behavioral adaptation to safety improvements is an important area for future behavioral research.

The behavioral sciences also contribute to methodological advances in the study of injury causation and intervention effectiveness. They emphasize the importance of developing reliable, valid, and quantitative outcome measures related to attitudes, knowledge, and behaviors. This is extremely important for assessing the effectiveness of educational and regulatory interventions designed to induce behavioral change. They have also contributed to the refinement of study designs widely used in injury research, particularly by epidemiologists (see following section). A more prominent role for behavioral scientists in suicide and violence research is warranted, given the need for increasing methodological rigor in these areas of injury research (see NRC [1993, 1994, 1996, 1998]). Finally, behavioral research has cultivated new research tools, such as qualitative research. By using observation, in-depth interviews, and focus groups, qualitative research strives to make sense of, or interpret, a particular behavioral or clinical issue (Greenhalgh and Taylor, 1997). However, because it lacks quantitative rigor, qualitative research is best used to describe new phenomena and generate research questions and hypotheses (Poses and Isen, 1998).

The tools of epidemiology may be used to design studies to elucidate the nature or cause of injury and to determine the effectiveness of interventions. Over the past decade, epidemiologic studies have advanced the injury field by quantifying the relationship between risk factors and injury. Risk-factor identification ranges from identification of risky behavior and at-risk populations to