How public health campaigns promote public health disparities

It is often claimed that interventions aimed at promoting healthy behaviors tend to be most effective among people whose behavior least needs to change and least effective among those most in need of change. If true, the inevitable result would be widening disparities in health engagement between these groups. Using a between-subjects experimental design, this study examined the effects of a directive advocacy message based on the theory of planned behavior (TPB) on groups with different pre-existing levels of engagement in healthy behaviors. The results confirmed that, compared to effects of a non-persuasive control message, the TPB-based message produced greater disparities in engagement between the group lowest in pre-existing health engagement and groups with greater pre-existing levels of engagement. The study suggests well-intended public health initiatives may seem to provide a net benefit to society but, in fact, actually contribute to the persistence of the disparities they attempt to address.