for whom it is not. The goal is to target segments of people who will respond in a similar way so that a health message can be designed to maximize its relevancy. Segmentation is now considered a necessary step in the process of design and development of communication campaigns (Atkin and Freimuth, 1989; Grunig, 1989; Rogers and Storey, 1987; Slater et al., 1996). Health campaign planners require quantitative evidence to define or identify potential audience segments and both quantitative and qualitative evidence to understand those segments well.
The idea of a heterogeneous audience is a core assumption of most current health communication programs. However, only some of that heterogeneity for a particular health behavior will correspond to the diversity categories that are the focus of this volume: race, ethnicity, gender, age, economic status and social class, education, and sexual orientation. For example, regarding marijuana use, although age matters a great deal, the genders are similar. Sexual orientation clearly is related to risk of sexually transmitted disease, but may not be a core issue for planning a campaign to encourage diabetes screening. For some behaviors and for some audiences, other factors may be much more useful for segmenting audiences than any of the focus diversity categories. For example, developers of antidrug campaigns for youth know that risk of drug use initiation is predicted by prior smoking and alcohol use and by a personality variable—sensation seeking—none of which are closely related to the traditional demographic categories used for monitoring attention to diversity (except for age). However, even in these circumstances, when the traditional diversity variables may not predict behavioral status or even the causes of behavior, these diversity categories may be relevant to the channel choices and the message executions. Thus antidrug messages may address the same behavioral target and assume the same motivations for drug use for all current nonusing youth, but use different celebrities (’N Sync for young white teens and Mary J. Blige for young African-American teens) as sources for antidrug messages or buy media time on different channels (an afternoon soap opera for girls and a football game for boys).