Toward a framework for intervention channels: Reach, involvement, and impact

PURPOSE: This paper presents a Media Channel Framework to help intervention planners make media choices. The key elements of this framework are two dimensions on which media differ: the reach/specificity and arousing/involving dimensions. Whereas a medium's reach or specificity determines the size of the population affected by an intervention, a medium's ability to arouse or involve audience members affects the level of outcome brought about the campaign-that is, whether awareness, knowledge, attitudes intentions, or behavior is affected. METHODS: Cross-sectional data on individuals' media use from the Stanford Five-City Project (FCP) are used to examine the reach and specificity of mass media. A meta-analysis of data from 57 evaluations of media-based interventions over the past 10 years explores the effectiveness of media in light of both dimensions of the framework. RESULTS: The FCP data confirms that television is a high-reach medium, whereas broad readership of newspapers, magazines, and radio have more specificity. The review of evaluation studies shows that interventions relying solely on television produced the fewest significant behavioral changes, while interventions relying solely on print channels produced the most behavioral changes. To the extent that behavioral change depends on the cognitive involvement of audiences, this finding supports a framework in which television is emotionally arousing, while print media are more involving. CONCLUSIONS: These results suggest that structural features of mass media can affect behavioral outcomes of campaigns. Planners should therefore consider the reach/specificity and arousing/involving dimensions of the Channel Framework when choosing mass media for public health interventions.