A Meta-Analysis of the Effect of Mediated Health Communication Campaigns on Behavior Change in the United States

"By establishing more realistic goals, planners can better set funders' and staff members' expectations about what can and cannot be accomplished by a single media campaign. In addition, our figures can become a benchmark against which new campaigns can be measured. Planners are frequently innovating with new channels, message strategies, and timing. Now they will be able to judge whether the innovations were helpful or not."

This article shares the results of a meta-analysis of studies of mediated health campaigns in the United States, with the purpose of estimating the average effects of these kinds of campaigns for different health topics and types of behaviours: tobacco and alcohol consumption, seat belt use, cardiovascular health (diet and exercise), mammography, dental care, and sexual behaviour campaigns. The focus was on behavioural outcomes because behaviour change is often the "bottom line" goal of a campaign, even though is it more difficult to achieve than awareness of a problem, knowledge of a solution, or motivation for change. Drawing on the diffusion of innovations (Rogers, 1983) and other approaches, the authors classified behaviours by: the adoption goals of commencement, prevention, or cessation; whether the behaviours were addictive or not; and the rate of behavioural compliance before the campaign.

In short, the study found that mediated health campaigns have small but tangible effects in the short term, changing the behaviour of about 8% of the population. "It is crucial to remember that small percentage changes may affect very large numbers of people in a community, state, or national campaign. An 8% change in a city of 100,000 targeted adults would yield 8000 more people engaging in the desired health behavior. The modest changes caused by media campaigns could have an important impact on public health."

Campaigns with an enforcement component - e.g., penalties imposed for lack of seat belt use - were more effective than those without. Other findings included: "Among the campaign characteristics tested in the present research, the one that explained the most variance in campaign effect size was the topic of the campaign. Seat belt, oral health, and drinking [alcohol] campaigns tended to be slightly more successful than campaigns on other topics....Although it appeared at first that it was easier to promote the adoption of a new behavior than to prevent a new undesirable one from starting or extinguish an old one, the effect of enforcement messages was largely responsible for that relationship. The mean change in percent of population performing the target behavior was 17% for enforcement campaigns, 5% for nonenforcement adoption campaigns, 3% for prevention campaigns, and 3% for nonenforcement cessation campaigns, among the studies that measured the percentage change. Cessation of an addictive behavior was particularly difficult to attain in interventions..."

To predict campaign effect sizes for topics other than those explored in this study, the authors note that researchers can take into account whether the behavior in a cessation campaign was addictive and whether the campaign promoted the commencement of a new behaviour versus cessation of an old behaviour, or prevention of a new undesirable behaviour.