vidual skills or strive to change individual behavior. At the social level, interventions attempt to bring to bear the broader resources deriving from contacts with the individual's family, friends, or social network or to change behavior patterns in family groups. At the organizational level, interventions are implemented in specific settings or units such as work sites or schools and target group change. Interventions at the population level are actions targeted at entire communities, towns, or states. In practice, intervention programs can be directed at one level at a time or can cross levels (Sorenson et al., 1998). Indeed at any one time, for example, public health efforts could promote better diets at the community level, schools could offer heart healthy lunches instead of the current fast food options, and individuals could be advised by their primary care providers to reduce fat in their diets.
Behavioral and social interventions can target either prevention or treatment, although these goals frequently coalesce in practice. For example, altering diet or increasing exercise can prevent the initial onset of cardiovascular problems, improve recovery, and prevent reoccurrence of cardiovascular problems. In general, interventions aimed at altering health risk behaviors have both preventive and treatment effects.
Successful intervention programs function on multiple levels (Sorensen et al., 1998). The benefits of targeting individuals at high risk due to their previous or current behavior, such as heavy cigarette smokers, or to a genetic susceptibility such as that of cholesterolemia, is apparent. However, clinical models that intervene with only high-risk individuals miss the potential for preventing disease by addressing other underlying causes contributing to elevated risk. When underlying causes of illness, such as low socioeconomic status are widely distributed in segments of the population, small changes at the population level are likely to have significant effects on overall population-level health. Indeed, many of the new social risk factors, including poverty and social isolation, are better addressed at the family, organizational, or population level than at the level of the individual. Similarly, when risk, such as widespread physical inactivity and overweight, is widely distributed, small changes at the population level to encourage activity (Chesney et al., 2001) are likely to yield greater improvements in the population-attributable risk than larger changes among a smaller number of high-risk individuals (Velicer et al., 1999).
The success of many health-related activities depends on the decisionmaking competence of the individuals involved. In their day-to-day lives people need to make good choices about diet and exercise, about the safety of their homes and vehicles, about the management of alcohol and anger, and about how to monitor their health status. When problems arise, they must decide when and how to present themselves to health care professionals as well as which treatments to follow. As practitioners, health care