Science is being used in different ways by different party policymakers, according to new research.

From climate change to the public health crisis to advances in artificial intelligence, social challenges are essentially linked to scientific advances over generations. However, as politics becomes more polarized, the role of science in the science of law is increasingly contested.

A new Northwest study published in Science, which analyzes Congressional Committee Reports, Commission hearings, and policy documents from think tanks around the country, found that despite the steady increase in science policy citations over the past 25 years, Democrats tend to cite more influential science than their Republican counterparts in policy making.

A research team led by Dashun Wang and Alexander Farnas of Kellogg Management School observed systematic differences in the amount, content and character of scientific data cited in policies by partisan facts in the US.

Wang is Kellogg Chair of Kellogg, Professor of Management and Organization for Kellogg and Industrial Engineering and Management Sciences at Kellogg and McCormick School of Engineering and Applied Science, Director of Kellogg’s Center for Science and Science (CSSI), Co-Director of Northwest Innovation Institute and Kellogg’s Ryan Institut on Plenspedity. Furnas is an assistant research professor at Kellogg CSSI.

“In spite of recent cases of bipartisan support for science, our study revealed partisan differences in the use of science to highlight the deep tensions in the connection between science and politics,” Wang said.

Regardless of political parties, the use of science in policy making has increased over the past 25 years. “In today’s society, many of the social challenges are inherently related to the latest scientific developments we see,” Wang said. “It’s welcome to see the policy makers who are increasingly dependent on scientific evidence and the policy documents they generate.”

Who cites science, when and how?

Science may be more open to public spaces than it is now, but there was a clear gap when researchers analyzed policy documents created by left-leaning politicians against their Republican counterparts. They observed systematic differences in the amount, content and personality of science used.

“We found that policy documents from Democratic-controlled committees are almost 1.8 times more likely to cite science than committees in Republican-controlled committees,” Wang said. “When it comes to Think Tanks, left-leaning tanks could cite five times more science than those produced by right-leaning ones.”

Under democratic control, the researchers noticed that the House Energy and Commerce Committee cited science on abortion, drunkards, youth and e-cigarettes, energy production and infrastructure, gun violence and mental health. When Republicans ruled the committee, they were more likely to cite science on medical insurance costs, air pollution, opioids, or high school athletic injuries. But even when they focus on the same policies and issues, they don’t cite the same science.

“We found that all the papers cited are by constructionists, but only 5% to 6% of scientific citations are shared by Republicans and Democrats,” Wang said. “This means there is much less bipartisan engagement with the scientific literature than expected. They don’t seem to cite the same paper.”

Trust is often understood as a reason why science may or may not be cited in policy making. Researchers have discovered that the significant decline in conservative trust in science over recent decades could be threatening confidence in science as a result of an increase in political polarization in the United States.

“Science should be considered a politically neutral and reliable source,” Wang said. “However, as our research suggests, various political parties support their claims by citing different scientific sources, which raises the question of whether science is selectively used to support existing beliefs and agendas.”

Decompose the numbers

The researchers have analyzed 191,118 policy documents issued since 1995 by all Congressional Committee reports, committee hearings since 2001, and since 1999 by 121 US-based ideological think tanks. Linking the two gave us the opportunity to examine partisan differences in the use of science in policy.

Think Tanks (a group of experts providing advice and ideas on economic and political issues) was an important data set for researchers to consider when analyzing where and what types of science were cited.

“Thinktanks are research areas that have a very profound impact in the United States, unlike other democracies,” Farnas said. “Policy production, the generation of ideas, and the construction of evidence happen in these private institutions. It was important to introduce them into conversations along with formal government agencies.”

The researchers also looked into 3,500 American political elites and civil servants and asked how much they trust or distrust science, regardless of political party. They found that 96% of democratic elites trust either scientists, either fully or partially, to spread their fair knowledge, compared to 63.7% of Republican elites.

The impact of today’s real world

Researchers continue to explore how political dynamics are shaped in the relationship between science and policy making, including the ways in which evidence is generated, interpreted and used in different institutional settings.

If scientific evidence is questioned, there are real consequences as well. Furnas said the current tariffs and economic conflicts are blatant examples.

“There is economic science on the impact of tariffs. There is a general economist consensus view on evidence-based US trade policy,” Furnas said. “But we may see Cherry picking scientific facts because different partisan actors have different commitments, and that’s how we gain policy uncertainty.”