On Sept. 3, Florida’s surgeon general, Joseph Ladapo, announced that the state would eliminate school vaccine mandates. Experts argued the move reflects politics more than science. For many, it was yet another example of politics overshadowing clear scientific evidence in policymaking.
One common belief is that policymakers make decisions based on ideology first. Evidence comes second, if at all. But is that always true?
Political science research shows that ordinary citizens are not always swayed purely by partisanship. People can update their views when given strong policy information. But can policymakers also change their views, based on evidence? This big question is what motivated our study.
How to test policymakers directly
To explore this question,we ran an online experiment with 232 elected local policymakers across the United States. Our participants included mayors, city council members, county commissioners, and school board officials who regularly make decisions that affect their communities.
We recruited them by sending email invitations through Qualtrics, an online survey platform. The contact list came from Quorum, a database of more than 15,000 local officials.
We studied policies favored by both conservatives and liberals. These included crime-reduction strategies like focused deterrence and self-defense laws like stand-your-ground – strategies favored by conservatives. We also looked at liberal ideas like cash assistance and rent control for lower-income constituents.
In our survey, we randomly assigned each policymaker to view strong or weak evidence on two of the four policies. Strong evidence came from multiple studies with large samples. Weak evidence, in contrast, came from single small-sample studies or anecdotal reports. All of the evidence came from real-world sources – these were not examples we created. For example, a strong message on cash transfers drew on scholarly reviews of U.S. programs showing this assistance is not associated with reductions in work. A weak message on this policy cited a local news story about one small program in Birmingham, Alabama. Each policymaker rated their support for each policy on a seven-point scale, from “disagree strongly” to “support strongly.” They also rated their familiarity with each policy and the quality of the evidence to which they were exposed.
What we found
The results were clear. When policymakers saw strong evidence, their support for a policy rose by about one point on a seven-point scale. For example, strong research on cash transfers and rent control boosted support for these programs, by more than a full point. Focused deterrence and stand-your-ground laws showed similar gains. Weak evidence barely moved policymakers’ opinions.
The role of ideology was mixed in how policymakers rated the strength of the evidence. On rent control, conservative policymakers were more likely to rate weak evidence as convincing, but that divide disappeared when the evidence was strong. On cash transfers, the opposite happened. Conservatives were less persuaded even when the evidence was strong. For the other two policies, ideology didn’t seem to make much difference. However, ratings of the strength of the evidence are secondary in our view to the influence of evidence on support for policies. Policymakers may be partisan to the core. But strong evidence still mattered.
Why this matters
Some readers may wonder how far these findings go. In high-profile debates on issues like vaccines, partisan pressure may be stronger than for the issues we studied.
Given our sample, our study is most relevant to the local policymaking context, where issues typically attract less national attention. But the broader lesson holds. Weak evidence rarely changes people’s minds. Strong, credible research, on the other hand, can shift people’s views. Even among partisan officials, evidence quality mattered more than ideology.
There’s a simple message here. Producing rigorous evidence is only part of the challenge. Getting it to policymakers in clear and compelling ways is just as important. But yes, facts still matter, even in polarized times.
Daniel E. Bergan is a professor in the Department of Communication and James Madison College at Michigan State University. He studies a variety of topics in political communication, including the influence of persuasive messages on policymakers.
Kelechi Amakoh is a PhD candidate in political science at Michigan State University, a 2025–2026 Good Authority fellow. His research focuses on elite communication and how it shapes voter perceptions and democratic attitudes in multiethnic societies.
Dustin Carnahan is an associate professor in the Department of Communication in the College of Communication Arts and Sciences at Michigan State University. His research specializes in how communication processes shape citizens’ understanding of politics, with recent work centering on the role of political misinformation.
Dan Hiaeshutter-Rice is an assistant professor in Michigan State University’s Department of Advertising and Public Relations. He is a political communication and computational social science researcher.
