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Disaster preparedness: Will a “norm nudge” sink or swim?

Jantsje Mol, Center for Research in Experimental Economics and Political Decision Making (CREED), University of Amsterdam

In these times of unprecedented climate change, one critical question persists: how do we motivate homeowners to protect their homes and loved ones from the ever-looming threat of flooding? This question led to a captivating behavioral science study, born from a research visit to the Wharton Risk Management and Decision Processes Center in 2019 (currently the Wharton Climate Center). Co-founded and co-directed by the late Howard Kunreuther, the Center has been at the forefront of understanding and mitigating the impact of natural disasters. In this study, we explored the potential of social norms to boost flood preparedness among homeowners. While the results may not align with initial expectations, they shed light on the complexities of human behavior, the significance of meticulous testing, and the enduring legacy of a visionary scholar.

The Power of Social Norms

Before we delve into the results, let’s take a moment to understand what social norms are and why they matter. Social norms dictate what is considered acceptable or expected in a given community. A popular behavioral intervention based on social norms is a norm-nudge: reading information about what others do (say, energy saving behavior of neighbors or tax compliance rates of fellow citizens) may adjust one’s own behavior closer. Norm-nudges are cheap, easy to implement and less prone to political resistance than traditional interventions such as taxes, but they might be ineffective or even backfire. Norm-nudges have been applied to health, finance and the environment, but not yet to the context of natural disaster risk-reduction.

Testing the Waters: Descriptive Social Norm-Nudges

In this study, we designed several norm-nudges to increase flood perparedness. For instance, if homeowners are informed that a majority of their neighbors have fortified their homes against floods or have evacuation plans in place, they may be more inclined to follow suit. We tested different norm-nudges with information about the decisions of previous respondents, and an innovative focusing norm treatment where we asked participants to guess what others would do.


The Study’s Methodology

We conducted a thorough study involving homeowners in flood-prone areas across two countries (The Netherlands and Spain). We sampled only homeowners because they are in the position to execute the intention (of installing damage-reducing measures). Respondents played one of the four variants (see Figure 1) of the flood risk investment game and answered a few survey questions. The study was high-powered (n = 605 in Spain and n = 1200 in the Netherlands) and preregistered

The Surprising (Lack of) Results

In the world of scientific research, outcomes can often surprise us, and this study was no exception. The results showed that none of the three variants of social norm-nudges lead to a significant increase in flood preparedness among homeowners (see Figure 2). While this may seem like an unexpected turn, but it is a crucial part of the scientific process. In a field where success stories often steal the spotlight, null results play an equally important role. They tell us what does not work, guiding us toward more effective strategies. It highlights the necessity of rigorous testing to truly understand the impact of behavioral interventions.

No Norm-Nudges in Unfamiliar Contexts

We are not the first to report that norm-nudges do not always work as intended. In a related study,  social norm-nudges were designed to convince consumers to buy carbon offsets for flight tickets, with no effect. The author argues that the main problem is that carbon offsetting is an unfamiliar concept to most participants, in contrast to other domains where norm-nudging has been effective, such as recycling, organ donation, or charitable giving. This explanation also fits our findings.

Honoring Howard Kunreuther’s Legacy

Howard Kunreuther
(Photo: Wharton School Press)

Before we conclude, we pay tribute to one of the co-authors of this study, Howard Kunreuther who died on 1st August 2023. His dedication to advancing our understanding of risk, resilience, and disaster preparedness has left an indelible mark on the field. His legacy continues to inspire researchers and policymakers to seek innovative solutions to complex challenges. In an earlier blog for BPP Kunreuther and Slovic draw lessons from the Covid-19 pandemic for action on climate change, whilst there is improved appreciation: “The curve looks and feels innocent and benign, and easy to ignore in its early stages. But suddenly, and sooner than you expect, it takes off in a torrent of harm that can be overwhelming.”


In an era marked by increasing climate-related risks, finding effective ways to enhance disaster resilience is more critical than ever. While our study may not have yielded the expected results, it reinforces the importance of methodical testing and the need to continuously explore new avenues for improving disaster preparedness. 

This blog was written by Jantsje Mol and is based on the (open access) Behavioural Public Policy article All by myself: Testing descriptive social norm-nudges to increase flood preparedness among homeowners by Jantsje Mol, Wouter Botzen, Julia Blasch, Elissa Kranzler and the Howard Kunreuther.

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