The annual International Behavioural Public Policy Conference 2025 at Cambridge University [June 25-26]

Behavioural Transformations 2025 at London School of Economics [June 27-28]

Annual European Association of Environmental and Resource Economists Conference in Leuven [July 1-4]

The annual Advances in Field Experiments 2025 Conference at London School of Economics [September 5-6]

9th Workshop on Experimental Economics for the Environment [September 10-11] 

Sustainable Food Systems Symposium [September 16-17]. Keynote Lecture.

FINBEPOL Keynote Lecture. Finnish PMO BI Day [September 20]

BSRIA Briefing 2024 - Sustainable Futures: Redefining Retrofit for Net Zero Living. Keynote Lecture [November 22]

Warwick Economics Department Seminar Series [November 27-28]

Norway Tax Administration and Oslo RCT Brown Bag Seminar [December 4] (online)

WHO Athens Keynote Lecture in Quality of Care Conference [December 10] (online)

Imperial College Business School CEPHI Seminar [January 13, 2025]

UCL Behavioural Economics for the Environment Lecture [27 January, 2025]

OECD Policy Brief  Launch “Green Lift, Mind Shift" Academic Keynote [29 January, 2025]

Pakistan Climate Policy Dialogue: BPP Keynote [19 February, 2025]

Oxford Behavioral Insights Group (BIG) Lecture [20 February 2025]

UK Ofcom Lecture [3 March 2025] 

Brighton College - Masterclass on Nudging [11 March 2025]

OECD- Cambridge Workshop on Trust in Institutions [20 March 2025]

MSH Alps, University Grenoble Alpes Workshop on Behavioural Influence and Resistance to Influence [14 April 2025]

CERAG Conference on Behavioural Science and Public Policy [20 April 2025]

NoBeC Keynote Lecture, University of Penn [8 May 2025]

Council of Europe, Behavioural Science Seminar [12 May 2025]

Pellervo Economic Research PTT in Helsinki  Invited Lecture [16 May 2025]

OECD Symposium on Driving Practical Public Sector Innovation [22 May 2025]

Transport, Energy and Climate Economics (TrEnCE) Seminar Paris PSL Dauphine [4 June 2025]

Abstract: Current food choices have a high environmental footprint, rendering them incompatible with both climate objectives and broader sustainable development goals. Transitioning to "planetary health diets" is important and required at scale urgently. In this chapter, I present an overview of the current food policy landscape using my newly proposed EATPath Toolspace, which as the name suggests, outlines food policies along different stages of the food demand, namely purchase, consumption and waste. I highlight three main challenges to this toolspace, before proposing newer behavioural and economic policy alternatives. First, I highlight that food policy has predominantly favoured softer approaches, such as behavioural "nudges", which subtly alter choice environments without imposing bans or raising costs. While behavioural insights can be effective, scaling them has limitations, often also raising ethical concerns regarding their use. To overcome this challenge, I argue in favour of a modified toolkit, nudge+, which embeds reflection into the design of (food) nudges making them effective and more ethical. Second, I highlight the need to urgently price meat and dairy more accurately by means of economic fiscal policies, such as meat taxes, voluntary carbon offsets, and subjecting the agricultural sector to tradable emission quotas. Lastly, I highlight the need to adopt a more open-minded approach to policy combinations and sequences, underscoring the value of leveraging policy complementarities and synergies between both behavioural and economic policies. If we are to seriously address the climate crisis and mitigate the emissions associated with livestock, urgent action is required. The time to act is now.

Abstract: People differ in their underlying economic preferences and needs for energy retrofits. Accelerating the energy transition, therefore, requires tailoring personalised solutions for distinct groups of individuals. In this paper, we create behavioural phenotypes of green energy investors in the residential sector of the Netherlands. Using a latent class analysis on a representative sample of 2,245 respondents, we identify four distinct classes of investors: Comfort-driven Rationalists, Financially Driven Rationalists, Policy-driven Environmentalists, and Erratic Choosers. We innovate upon the literature by linking class profiling to economic preferences and behavioural biases, alongside socio-demographic and household characteristics. Our findings can help practitioners design bottom-up tailored behavioural interventions to accelerate the uptake of green energy investments.

Abstract: Meat consumption and willingness to reduce it may be linked to political ideology, with a common assumption that left-leaning individuals favour meat reduction policies more than right-leaning ones. However, rigorous evidence is lacking on this point. This study examines whether support for meat reduction policies varies by self-reported political ideology. Using a conjoint experiment with nationally representative samples from Denmark, Germany, the Netherlands, and the UK (N=2,008), we randomly vary four attributes of a hypothetical meat tax: cost, revenue redistribution, motivation, and outreach. We find that right-wing voters support a baseline meat tax more than left-wing voters, but their support decreases when policies involve revenue redistribution, incorporate environmental costs, or emphasize environmental over health concerns. These patterns are partly explained by differences in Schwartz values across ideological groups. Our findings highlight the role of narratives in shaping political debates on meat taxation.

Abstract: Are stringent vaccine promotion policies associated with higher uptake, even when people are hesitant about the vaccine? In a survey of G-7 countries, 22% of respondents (n=42,217) say they do not trust the COVID-19 vaccine, but half of them nonetheless take up at least one vaccination. We investigate a range of factors associated with vaccination, focusing on the stringency of vaccine promotion policies, which change the costs and benefits of immunization choices. We show that living in a country with more stringent vaccination policies is positively associated with uptake of the initial vaccination protocol, including among people who are skeptical about the vaccine. The association between policy stringency and uptake of the booster vaccine is also positive among those who are skeptical about the vaccine. However, this association is not differentially stronger compared to the group who trust the vaccine. Our findings suggest that policy stringency can play a key role in vaccine uptake. Our findings raise questions for policymakers, in finding the appropriate balance between persuasive and coercive policies to promote policy goals.

Abstract: Understanding the mechanisms through which behavioural interventions work remains a critical challenge in behavioural science. While randomized controlled trials (RCTs) provide reliable evidence for intervention efficacy, they are seldom designed to reveal the underlying causal pathways that drive observed outcomes. We introduce a comprehensive data-driven methodological protocol -- BriDGE -- that combines advanced causal inference techniques, such as Directed Acyclic Graphs (DAGs), causal discovery algorithms, and Generalized Additive Models (GAMs), to enhance mechanistic insights in behavioural applications. BriDGE modifies conventional experimental analysis with a stepwise approach including DAG-based hypothesis formulation, modelling of nonlinear relationships with GAMs, and detailed mediation analysis. Using bootstrapping and sensitivity checks, BriDGE ensures robust and reliable detection of both direct and indirect effects. We use a simulation study to validate BriDGE's ability to identify complex causal mechanisms, offering researchers with a robust framework for deepening understanding of causal mechanisms and optimizing intervention design. There are natural limitations of BriDGE -- we discuss their implications when applied to public policy. We call for a greater integration of these methods in the toolkit of applied policy analysis to bridge the gap from “what works" to “why and how it works".

Abstract: Vegetarian diets can reduce global ecological costs. Yet meat continues to be culturally dominant, especially in the West. Does culture hamper the adoption of vegetarian diets? In an online experiment, we observed the intentions of 2,775 English participants to choose vegetarian food. We causally test if framing food options with culturally familiar names alters the effectiveness of a nudge promoting vegetarianism. Facing culturally familiar food does not change the effect of the nudge. However, exploratory analyses reveal that participants ask for lower monetary compensation for being forced to choose vegetarian food when it is culturally framed. Thus, welfare losses of hard policies, like bans, may be lower when alternative options look familiar.

Abstract: Behavioural nudges, such as defaults, improve human welfare by reducing choice overload. But how far should policy-makers go in reducing available choices?  Using a preregistered, online survey experiment, we randomly assign 1,518 UK citizens to two versions of the same opt-out default nudge aimed at encouraging charitable donations. In one version, the default was embedded in a list of multiple options, whereas in the other it was presented as a single choice. In both versions, participants could opt-out and choose any preferred donation amount. We find that when the default is embedded in a multiple-choice list, opting out rates and average individual donations are significantly higher compared to the standard single-choice default. Our findings suggest that encouraging active choosing alongside a default can improve agency without necessarily deteriorating behavioural outcomes.

Abstract: Respondents from around the world are financially incentivized to complete surveys in higher paying markets, and some respondents are even willing to falsify their credentials to do so. We propose a new cost-free method for identifying and excluding non-target respondents who see blank JavaScript-programmed experiments due to VPN usage. Using a dataset of 72,200 respondents in the G-7 countries, we show that 94 respondents (0.13\%) in our entire G-7 sample and 49 respondents (0.49\%) who report being from the United States are likely using virtual private networks (VPNs) to disguise their locations to qualify for surveys outside of their country. These non-target respondents provide low-quality responses, affecting external validity. Simple JavaScript programming can reject this rare type of non-target respondent from surveys administered using Qualtrics. 

Nudge+, a nudge for good thinkers.  Joint with Peter John. (Under consideration in Cambridge University Press)