Does communicating evidence of policy effectiveness influence public support for the policy?

Increasing the prices of products that harm health is an effective intervention for changing behaviour to improve health, but public support for such interventions is generally low. When a proposed intervention is unpopular, yet has the potential to have an impact, policy makers may seek to increase public support. Research associate Dr James Reynolds, working with Professor Theresa Marteau and Dr Mark Pilling at the Behaviour and Health Research Unit, set out to test one set of promising approaches for doing so.

In a series of experiments involving nearly 10,000 people, the researchers tested ways to communicate quantitative evidence of the effectiveness of a hypothetical tax on confectionery to help tackle childhood obesity. The researchers used results from the first two experiments to improve their infographics and the accompanying numerical information provided to study participants. The third experiment, using the improved materials, showed increased support for the hypothetical tax, equivalent to increasing the number who support the tax from 45% to 49%.

“Communicating quantitative evidence of the effectiveness of a policy increased participants’ perceptions of the effectiveness of the policy at tackling childhood obesity and resulted in increased support for it. The changes in support were small yet potentially meaningful at a population level” – Dr James Reynolds, BHRU

Much uncertainty remains about the optimal methods of communicating risk and quantitative evidence.  In this research, different interventions that communicated the same core information had disparate effects on the comprehension of the information, the perceptions of how effective the tax was, and support for the tax. So, research to evaluate different formats for communicating quantitative evidence from the perspective of both comprehension and belief change is an important next step.​

Communicating quantitative evidence of policy effectiveness and support for the policy: Three experimental studies. Reynolds JP, Pilling M, Marteau TM. Soc Sci Med.

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