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The selective use of physics knowledge in policy: how interdisciplinary physics bridges subfields and shapes policy influence

By analyzing a novel dataset linking American Physical Society publications to the Overton policy database, this study demonstrates that while interdisciplinary physics serves as a bridge for scientific visibility in policy discourse, actual policy influence is driven more by the political salience of specific subfields, such as geophysics, rather than by interdisciplinary breadth.

Original authors: Jeongmin Lee, Jisung Yoon

Published 2026-02-12

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CC BY 4.0

Original authors: Jeongmin Lee, Jisung Yoon

Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

The "Translator" Problem: How Physics Speaks to the World of Power

Imagine you have two very different groups of people living in the same city.

On one side, you have the "Deep Divers" (the Scientists). They spend their lives in massive, high-tech libraries, studying the tiniest atoms or the most complex mathematical equations. They care about absolute truth, extreme detail, and things that might not matter for another hundred years.

On the other side, you have the "Firefighters" (the Policymakers). They are constantly running from one emergency to the next—climate change, pandemics, or economic crashes. They don't have time to read a 500-page treatise on subatomic particles; they need to know, "What can I do right now to stop this fire?"

The problem? They speak different languages.

A new research paper by Jeongmin Lee and Jisung Yoon explores this "language barrier" by looking at how physics knowledge actually makes its way into government decisions.

1. The Mismatch: The Buffet vs. The Grocery List

The researchers found a massive "mismatch" between what scientists produce and what policymakers actually use.

Think of it like a giant buffet. The scientists have prepared a massive spread of incredibly specialized dishes: "Quantum Field Theory Soup" and "Elementary Particle Salad." These are the heavy hitters of the scientific world.

However, when the policymakers arrive, they don't touch the specialized dishes. Instead, they head straight for the "Interdisciplinary Buffet"—the dishes that mix different flavors together, like "General Physics" or "Complex Systems." They want the "all-in-one" meals that are easy to digest and can be applied to many different problems at once.

2. The "Bridge" Builders (Interdisciplinary Physics)

The study highlights a special group of scientists: the Interdisciplinary Physicists.

In the world of science, these people act like Universal Translators. If a specialized scientist is a master of a very specific, ancient dialect, the interdisciplinary physicist is the person who speaks both that dialect and the common language of the world.

The researchers used "network analysis" (mapping how ideas connect) and found that these interdisciplinary fields act as the glue or the bridges of the entire system. They take the abstract, "heavy" math of physics and turn it into something a politician can actually use to write a law.

3. Visibility vs. Influence: The "Famous" vs. The "Powerful"

This is the most surprising part of the paper. The researchers discovered a huge difference between being visible and being influential.

Visibility (The Celebrity Effect): Interdisciplinary physics is very "visible." It gets cited a lot. It’s like a celebrity walking into a room—everyone notices them, and they are mentioned in every conversation.
Influence (The Kingmaker Effect): Just because you are "visible" doesn't mean you are "influential." The researchers found that while interdisciplinary physics gets people talking, it doesn't always change the actual laws.

So, what actually has real power?
The study found that Geophysics (the study of the Earth) is the real heavyweight. Why? Because of Climate Change.

Think of it this way: Interdisciplinary physics is like a popular influencer on Instagram—lots of likes, lots of mentions. But Geophysics is like the Weather Report. When the Weather Report says a hurricane is coming, the government doesn't just "mention" it; they move the entire city. Because climate change is a massive, global priority, the physics used to study it becomes "standardized" (like the IPCC reports). Once that knowledge becomes the "official rulebook," it gains a massive amount of downstream power.

The Big Picture

The paper tells us that science doesn't just "flow" into policy like water into a glass. Instead, it is filtered, selected, and translated.

If you want to change the world with science, it isn't enough to be the smartest person in the room (the Deep Diver). You also have to be able to build a bridge (the Translator) or provide the essential truth that everyone is already looking for (the Weather Report).

Technical Summary: The Selective Use of Physics Knowledge in Policy

1. Problem Statement

As global challenges (climate change, AI regulation, public health) become increasingly complex, the demand for evidence-based policymaking has surged. However, a fundamental "two-communities" gap exists between scientific research (supply-driven, long-term, specialized) and policymaking (demand-driven, immediate, problem-oriented). While scientific citations in policy are increasing, it remains unclear how science is selectively mobilized. Specifically, the authors investigate whether certain forms of scientific knowledge are preferred for "visibility" (entry into discourse) versus "influence" (downstream impact on subsequent policy) and how interdisciplinary physics acts as a bridge in this process.

2. Methodology

The study employs a novel, large-scale data linkage approach and advanced computational techniques:

Data Linkage: The authors link a subset of the Overton database (757 policy documents from governments, IGOs, and think tanks) with the American Physical Society (APS) corpus (1,156 unique physics articles). This allows for a directional analysis of how specific physics research enters policy.
Classification: Scientific content is categorized using the Physics and Astronomy Classification Scheme (PACS), grouping papers into ten major subfields (e.g., Condensed Matter, Interdisciplinary Physics, Geophysics).
Weighting Scheme: To prevent bias from long bibliographies or multi-coded papers, a fractional weighting scheme is used to normalize the contribution of each citation at both the document and paper levels.
Thematic Modeling: Latent Dirichlet Allocation (LDA) is applied to policy metadata to identify six dominant policy themes (e.g., Energy & Climate, Global Security).
Network Analysis: A weighted co-citation network of PACS codes is constructed. The authors use a disparity filter to extract the structural backbone and the Louvain algorithm for community detection to identify functional clusters of physics knowledge.
Statistical Modeling: Two Ordinary Least Squares (OLS) regression models are used:
1. Visibility Model: Predicts the likelihood of an academic paper being cited by policy (dependent variable: $\log(\text{PaperCitations})$ ).
2. Influence Model: Predicts the downstream impact of a policy document (dependent variable: $\log(\text{PolicyCitations})$ ).

3. Key Contributions

Identification of Structural Mismatch: The paper quantifies the divergence between the "supply" of physics (dominated by Condensed Matter and Particle Physics) and the "demand" of policy (which favors Interdisciplinary and General Physics).
Distinction Between Visibility and Influence: The study provides empirical evidence that being "visible" in policy discourse does not automatically translate into "influence" within the policy ecosystem.
Mapping the Brokerage Role: It demonstrates that interdisciplinary physics subfields act as structural "hubs" or "gateways" that connect specialized technical clusters to the policy sphere.

4. Key Results

Selective Mobilization: Policy documents disproportionately cite Category 0 (General Physics) and Category 8 (Interdisciplinary Physics). While Category 8 represents only 5.5% of academic production, it accounts for nearly 20% of policy demand.
Institutional/Thematic Heterogeneity:
- Think Tanks show a massive preference for interdisciplinary physics (over 77% of their citations).
- Government Agencies focus more on implementation-heavy research (Condensed Matter).
- Energy & Climate themes drive demand for materials science, while Global Economy themes drive demand for interdisciplinary/complex systems research.
The Brokerage Paradox: Network analysis shows that interdisciplinary areas have high betweenness and closeness centrality, acting as the "glue" for policy arguments. However, regression shows these areas do not significantly increase downstream policy influence.
The Geophysics Exception: While interdisciplinary physics facilitates entry (visibility), Category 9 (Geophysics/Astronomy) is the only field that significantly increases influence (a ~24% increase in downstream citations). This is attributed to the "standardization" effect of climate governance (e.g., IPCC reports), which embeds geophysics into high-circulation, authoritative policy infrastructures.

5. Significance

This research shifts the understanding of science-policy interaction from a simple "diffusion" model to a "selective mobilization" model. It reveals that the policy sphere does not consume science neutrally; instead, it strategically selects knowledge based on its ability to bridge disciplinary gaps or fit into established governance frameworks. The findings suggest that for scientific knowledge to move from mere visibility to systemic influence, it must be integrated into authoritative, consensus-building "knowledge infrastructures" (like the IPCC) rather than relying solely on its interdisciplinary or novel characteristics.