Health behavior theorists have long attested to the importance of social influences in health care decision making. For example, the prominent social cognitive theory is based on a construct of outcome expectations, of which social outcome expectations, or the value of the anticipated reaction of those in one's environment, plays a role. In essence, an individual will take into account the anticipated responses of approval or disapproval from his or her peers to a particular healthcare decision, and the perceived reaction will influence the decision made (Lusczynska and Schwarzer, 2007). The theory of planned behavior describes social influence as subjective norms, which are an individual's beliefs that significant others think they should engage in a behavior (Conner and Sparks, 2007). For example, a teenager may decide to start smoking if he believes that his friends have favorable attitudes towards smoking. Other models have focused on a more learning and observational approach, such as Interpersonal Behavior Theory, which speaks more specifically to subcultures and social group norms and their facilitative effect on health behavior decisions (Norman and Conner, 2007 ). Although these theories describe the effects of the social environment on an individual, at the basic level the individual consciously makes the decision about which health behavior to adopt. Social Network Analysis (SNA) is a technique that can be used to develop a richer description of the social environment. In addition to identifying peer groups, SNA creates a structural map of relationships in a given community, which can be examined at different levels, including the individual or subgroup level. In adolesc...... middle of paper ......detailed description of basic and intermediate ANS measures. For a basic glossary of SNA terms, refer to Hawe, Webster, and Shiell (2006). Social networks have been linked to health research and health outcomes as a measure of social support; the greater the number of relationships present, the better the health outcomes (for a recent example of this type of work, see Magliano et al, 2006). Another common use of SNA is to identify patterns of disease transmission. However, there are many other uses of SNA in health research, such as studying information transmission networks, examining the influence of social position on health behavior, building better partnerships through health organizational networks, and identifying individuals and relationships that will help spread health to the maximum. program message (Luke & Harris, 2007; Valente & Fosados, 2006).