The Certain Truth About Uncertainty

How Scientists Are Learning to Communicate What They Don't Know

Weather Forecasts Pandemic Models Climate Projections Scientific Research

Introduction

Imagine a weather forecaster who confidently predicts a 20% chance of rain. One person hears this and grabs an umbrella; another leaves it at home. Same information, different decisions.

Weather Forecasts

How we interpret probability in daily decisions reveals our relationship with uncertainty.

Pandemic Models

Life-or-death decisions depend on accurately communicating what we know and what we don't.

Now magnify this scenario to life-or-death situations: predicting the path of a hurricane, estimating pandemic infection rates, or assessing the safety of a new food additive. In each case, how scientists communicate what they don't know becomes as crucial as what they do know.

The Communication Challenge

Uncertainty isn't a flaw in science—it's an inherent part of how we understand complex systems. Yet for decades, a profound communication gap has persisted between scientists who quantify uncertainty and the decision-makers who must act on that information.

From climate models to economic forecasts, miscommunicated uncertainty can lead to everything from personal inconvenience to policy failures with global consequences. The good news? Researchers are now developing innovative strategies to bridge this gap, creating a new science of communicating the unknown.

The Uncertainty Gap: When Scientists Speak a Different Language

Two Worlds, Two Perspectives

A revealing 2025 study exposed just how wide the communication gap between scientists and decision-makers has become. Through in-depth interviews with 17 scientists and 15 decision-makers, researchers discovered fundamentally different approaches to uncertainty 1 .

Scientists' Approach

Scientists, trained in methodological rigor, typically express uncertainty through technical vocabulary and probabilistic language. They might say something is "statistically significant at the 95% confidence level" or present results with "confidence bounds" 1 .

This approach aligns perfectly with scientific standards but often baffles non-specialists.
Decision-Makers' Needs

Decision-makers—whether government officials, emergency managers, or corporate leaders—prioritize actionable insights. They need uncertainty communicated in ways that directly support decision-making across diverse contexts 1 .

As one emergency manager might wonder: "If you say a flood has a 30% probability, should I evacuate the city or not?"
Contrasting Perspectives on Uncertainty Communication
Aspect Scientists' Approach Decision-Makers' Needs
Primary Focus Methodological rigor Actionable insights
Communication Style Technical, probabilistic Practical, contextual
View of Uncertainty Inherent in models Factor in decision process
Key Concern Being precisely correct Making timely decisions

The Probability Problem

The challenges run deeper than mere terminology. Research reveals that people consistently struggle to interpret probabilistic information, especially when percentages or statistical terms are involved 1 . This isn't a intelligence issue—it's a cognitive one. Our brains aren't naturally wired to think in probabilities.

Interpretation Challenge

The European Food Safety Authority (EFSA) recognizes this challenge, noting that even qualitative terms like "negligible," "low," or "high" uncertainty are interpreted differently by different people 2 . Quantifying uncertainty on a percentage scale reduces ambiguity, but introduces other comprehension challenges 2 .

Beyond Risk: Understanding Different Types of Uncertainty

Before exploring solutions, it's crucial to understand what we mean by uncertainty. Economists like Professor Bo Sun draw a critical distinction between risk and uncertainty 3 .

Risk

Describes situations where we know the possible outcomes and can assign probabilities to each. Think of rolling a die—you know all possible outcomes and their exact probabilities 3 .

Known outcomes Known probabilities Quantifiable
True Uncertainty

Involves both unknown outcomes and unknown probability distributions. Events like Brexit, the COVID-19 pandemic, or major technological disruptions fall into this category—we didn't even know the full range of possible outcomes, let alone their probabilities 3 .

Unknown outcomes Unknown probabilities Unquantifiable
Uncertainty Spectrum in Scientific Assessment
Uncertainty Type Definition Examples Appropriate Communication
Statistical Uncertainty Quantifiable variation in data Measurement imprecision Confidence intervals, standard deviation
Model Uncertainty Limitations of scientific models Climate projections, economic forecasts Scenario analysis, model ensembles
Deep Uncertainty Unknown outcomes and probabilities Pandemic emergence, technological disruption Narrative scenarios, precautionary principle

Bridging the Gap: Strategies for Effective Uncertainty Communication

Learning from a Groundbreaking Experiment

The 2025 study on scientist-decision-maker dynamics provides valuable insights into what works—and what doesn't—in uncertainty communication. The researchers employed reflective thematic analysis of 32 interview datasets, using an iterative coding process with multiple cycles of refinement to identify key themes 1 .

Research Methodology
Participant Selection

Researchers identified scientists with expertise in developing or using hazard, risk, or climate models, primarily from government-funded research institutes, universities, and private research consultancies 1 .

Comparison Group

Decision-makers involved in emergency management within central and regional government, local authorities, and related agencies were selected 1 .

Data Collection

Semi-structured qualitative interviews were conducted, allowing flexibility and depth in exploring perspectives. Scientists were interviewed between May and August 2022, while decision-makers were interviewed between June and August 2021 1 .

Analysis Process

Interview transcripts underwent coding using NVivo software, followed by identification of sub-themes through reflective thematic analysis 1 .

Key Finding

The results revealed that the core issue wasn't simply technical language, but fundamental differences in how each group perceives the purpose of uncertainty information. Scientists viewed uncertainty communication as providing complete technical context, while decision-makers needed curated information tailored to specific decisions 1 .

The Visualization Solution

One promising approach involves developing user-focused uncertainty visualizations. Rather than presenting raw probabilities, effective visualizations contextualize uncertainty in decision-relevant terms.

Traditional Approach

Showing a hurricane path as a single line with "confidence bounds."

Single path with error margins

Improved Approach

Displaying multiple possible paths with intensity gradients indicating probability.

Multiple scenarios with probabilities

EFSA's Probability Scale for Communicating Uncertainty

The European Food Safety Authority has developed a practical framework for quantifying uncertainty in scientific assessments, using a probability scale adapted from the Intergovernmental Panel on Climate Change 2 :

Extremely likely 99-100%
Very likely 90-99%
Likely 66-90%
As likely as not 33-66%
Unlikely 10-33%
Very unlikely 1-10%
Extremely unlikely 0-1%

The Scientist's Toolkit: Essential Resources for Uncertainty Communication

Successfully communicating uncertainty requires both technical understanding and strategic approaches. Based on research findings, here are essential tools for effective uncertainty communication:

Structured Communication Framework

Professor Bo Sun emphasizes "anchor your decision with a structured, coherent framework that quantifies uncertainty and select strategies tailored to the specific context" 3 . This systematic approach reduces the psychological toll that uncertainty imposes on decision-makers.

Tailored Probability Scales

As shown in the EFSA framework, standardized probability scales bridge technical and non-technical audiences by providing both quantitative ranges and qualitative descriptions 2 .

User-Focused Visualizations

Moving beyond traditional error bars to decision-relevant visual representations that show how uncertainty affects specific choices or outcomes 1 .

Collaborative Processes

EFSA's development of uncertainty guidance combined expertise from social scientists, natural scientists, and communicators, recognizing that effective communication requires diverse perspectives 2 .

Uncertainty-Acknowledgment Language

Simple phrases like "based on current evidence" or "our confidence in this prediction is..." that normalize uncertainty rather than hiding it.

Interactive Tools

Digital platforms that allow decision-makers to explore different scenarios and understand how uncertainty affects outcomes in their specific context.

Conclusion: Embracing Uncertainty as Strength

As we navigate increasingly complex global challenges—from climate change to pandemics to economic turbulence—effectively communicating scientific uncertainty has never been more critical.

The Goal

The goal isn't to eliminate uncertainty, but to communicate it so effectively that decision-makers can act with appropriate confidence despite the unknowns. This requires scientists to move beyond technical precision toward practical relevance, and decision-makers to develop greater comfort with probabilistic thinking.

The Insight

Perhaps the most important insight comes from reframing how we view uncertainty itself. As Professor Sun notes, the goal is to "develop systematic approaches that allow us to harness uncertainty, not just survive it" 3 . In a world of increasing complexity, the honest acknowledgment of uncertainty isn't a weakness—it's a mark of sophistication and the foundation of both good science and wise decisions.

Final Thought

The next time you hear a weather forecast, consider the sophisticated communication challenges behind that simple percentage. That 20% chance of rain represents not just atmospheric science, but the evolving art of communicating what we know, what we don't, and why both matter for the decisions we make today.

References