Speaking truth in power: Scientific evidence as motivation for policy activism

Unelected administrative policymakers rely on the domain expertise and technical integrity of scientific information to maintain perceptions of legitimacy. The necessity that regulatory policymakers rely on sound scientific evidence has been formalized at the US federal level through executive order. Yet, the practical impact of scientific evidence on public support and mobilization for policies remains unclear. We investigate whether individual policy activists are more likely to participate in regulatory policymaking when a policy recommendation is substantiated by scientific evidence. We investigate how two separate groups within the public—policy advocates and policy experts—may be affected differentially by scientific evidence. In collaboration with a nationally active policy advocacy group, we conducted a randomized messaging experiment in which members of the group’s e-mail list are sent one of three versions of a policy advocacy message. Results indicate that reference to evidence published in peer reviewed scientific sources increased activism by roughly 1 percentage point among general activists, and decreased activism by 4-5 percentage points among scientific experts.