Christina Gravert
Behavioral economist | Associate professor University of Copenhagen | Co-founder Impactually

Research

My research interests include optimal policy design, nudging and sustainable behavior change. I conduct research in collaboration with public and private institutions in the fields of health behaviour and environmental sustainability. My focus is on innovating public policy by incorporating insights from behavioral economics and establishing the use of randomized controlled trials for evidence-based decision making. I have used laboratory, online, survey and natural and framed field experiments to understand human decision making.

Below you can find links to my published research papers, as well as abstracts of my current work in progress with links to working papers.

A selection of publications

2024

Gravert, Christina

Leveraging Field Experiments to Shape Environmental Policy Journal Article

In: Nationaløkonomisk Tidsskrift, vol. 2024, iss. 1, no. 8, 2024.

Abstract | Links | BibTeX | Tags: environment & climate, field experiments

2022

Effective carbon taxes need green nudges

Gravert, Christina; Shreedhar, Ganga

Effective carbon taxes need green nudges Journal Article

In: Nat. Clim. Chang., vol. 12, no. 12, pp. 1073–1074, 2022, ISSN: 1758-6798.

Abstract | Links | BibTeX | Tags: environment & climate, nudging

2021

Barron, Kai; Gravert, Christina

Confidence and career choices: an experiment* Journal Article

In: Scandinavian J Economics, vol. 124, no. 1, pp. 35–68, 2021, ISSN: 1467-9442.

Abstract | Links | BibTeX | Tags: confidence & grit

Gerhards, Leonie; Gravert, Christina

Grit and Peers: An Experimental Study on Peer Effects in Perseverance Journal Article

In: Clinical Psychiatry, vol. 7, iss. 4, 2021.

Abstract | BibTeX | Tags: confidence & grit

Gravert, Christina; Collentine, Linus Olsson

When nudges aren’t enough: Norms, incentives and habit formation in public transport usage Journal Article

In: Journal of Economic Behavior & Organization, vol. 190, pp. 1–14, 2021, ISSN: 0167-2681.

Abstract | Links | BibTeX | Tags: nudging

Carlsson, Fredrik; Gravert, Christina; Johansson-Stenman, Olof; Kurz, Verena

The Use of Green Nudges as an Environmental Policy Instrument Journal Article

In: Review of Environmental Economics and Policy, vol. 15, no. 2, pp. 216–237, 2021, ISSN: 1750-6824.

Abstract | Links | BibTeX | Tags: environment & climate, nudging

Gravert, Christina

Reminders as a Tool for Behavior Change Journal Article

In: SSRN Journal, 2021, ISSN: 1556-5068.

Links | BibTeX | Tags: reminders

2020

Gerhards, Leonie; Gravert, Christina

Because of you I did not give up – Peer effects in perseverance Journal Article

In: Journal of Economic Psychology, vol. 81, 2020, ISSN: 0167-4870.

Links | BibTeX | Tags: confidence & grit

2019

Gravert, Christina; Kurz, Verena

Nudging à la carte: a field experiment on climate-friendly food choice Journal Article

In: Behav. Public Policy, vol. 5, no. 3, pp. 378–395, 2019, ISSN: 2398-0648.

Abstract | Links | BibTeX | Tags: environment & climate, nudging

2018

Damgaard, Mette Trier; Gravert, Christina; Villalobos, Laura

Forgetful or Reluctant? Evidence on Reminder Response and Donor Behavior from Panel Data Book Chapter

In: The Economics of Philanthropy, pp. 219–238, The MIT Press, 2018, ISBN: 9780262348041.

Abstract | Links | BibTeX | Tags: charity & fundraising, nudging

Damgaard, Mette Trier; Gravert, Christina

The hidden costs of nudging: Experimental evidence from reminders in fundraising Journal Article

In: Journal of Public Economics, vol. 157, pp. 15–26, 2018, ISSN: 0047-2727.

Abstract | Links | BibTeX | Tags: charity & fundraising, nudging, reminders

Görlitz, Katja; Gravert, Christina

The effects of a high school curriculum reform on university enrollment and the choice of college major Journal Article

In: Education Economics, vol. 26, no. 3, pp. 321–336, 2018, ISSN: 1469-5782.

Abstract | Links | BibTeX | Tags: education

2017

Gneezy, Uri; Gravert, Christina; Saccardo, Silvia; Tausch, Franziska

A must lie situation – avoiding giving negative feedback Journal Article

In: Games and Economic Behavior, vol. 102, pp. 445–454, 2017, ISSN: 0899-8256.

Abstract | Links | BibTeX | Tags: lying

Damgaard, Mette Trier; Gravert, Christina

Now or never! The effect of deadlines on charitable giving: Evidence from two natural field experiments Journal Article

In: Journal of Behavioral and Experimental Economics, vol. 66, pp. 78–87, 2017, ISSN: 2214-8043.

Abstract | Links | BibTeX | Tags: charity & fundraising, nudging

Gravert, Christina

Pride and patronage - pay-what-you-want pricing at a charitable bookstore Journal Article

In: Journal of Behavioral and Experimental Economics, vol. 67, pp. 1–7, 2017, ISSN: 2214-8043.

Abstract | Links | BibTeX | Tags: charity & fundraising, nudging

2016

Görlitz, Katja; Gravert, Christina

The effects of the high school curriculum on school dropout Journal Article

In: Applied Economics, vol. 48, no. 54, pp. 5314–5328, 2016, ISSN: 1466-4283.

Abstract | Links | BibTeX | Tags: education

2013

Gravert, Christina

How luck and performance affect stealing Journal Article

In: Journal of Economic Behavior & Organization, vol. 93, pp. 301–304, 2013, ISSN: 0167-2681.

Abstract | Links | BibTeX | Tags: lying

Work in progress

Nudging, fast and slow: Experimental evidence from food choices under time pressure

with Paul Lohmann, Elisabeth Gsottbauer and Lucia Reisch

This paper explores the relationship between decision-making speed and the effectiveness of two nudges – carbon footprint labelling and menu repositioning – aimed at encouraging climate-friendly food choices. Building on Kahneman’s dual-process theories of decision-making, we examine whether these interventions are more effective in fast, intuitive (System 1) contexts compared to reflective, deliberate (System 2) ones. Using an incentivized online randomized controlled trial with a quasi-representative sample of British consumers (N=3,052) ordering meals through an experimental food-delivery platform, we introduced a time-pressure mechanism to capture both fast and slow decision-making processes. Our findings suggest that menu repositioning is an effective tool for promoting climate-friendly choices when decisions are made quickly, though the effect fades with extended deliberation. Carbon labels, in contrast, showed minimal impact overall but reduced emissions among highly educated, climate-conscious individuals under time pressure. The results imply that choice architects should apply both interventions in contexts where consumers make rapid decisions, such as digital platforms, to help mitigate climate externalities.

Working Paper

Carbon Taxes Crowd Out Climate Concern: Experimental Evidence from Sustainable Consumer Choices

with Alice Pizzo, Jan Bauer and Lucia Reisch

We examine the impact of a carbon tax on consumer choices via a large-scale online randomized controlled trial. Higher taxes generally reduce the demand for high-carbon goods. Compared to an import tax, a carbon tax reduces demand when the tax is zero (i.e., announced but not levied) but shows relatively higher demand for high-carbon goods when a positive tax is introduced. This contradiction of basic price theory is entirely driven by climate-concerned consumers. Our findings suggest that carbon taxes can crowd out climate concerns, leading to important implications for policy.

Working Paper

Intent to Inertia: Experimental Evidence from the retail electricity market

I study consumers’ choices in the retail electricity market. By conducting a large-scale survey experiment with 3% of the Danish working-age population, I have gathered data on respondents’ factual knowledge of the retail electricity market, their beliefs, preferences, and intentions to switch providers. Crucially, I can link their intentions with actual switching behaviors using nationwide smart meter data. My findings reveal a substantial gap between switching intentions and actions. This gap is exacerbated by my experimental interventions which 1) provide information about savings and switching costs and 2) decrease switching costs by offering free access to a switching service. While my interventions have large and significant effects on switching intention, they have only minor effects on actual switching behaviors. I calculate that a majority of consumers leaves money on the table by not switching. The low switching rates cannot be explained by biased beliefs or high switching costs. Demographics do not explain switching behavior, however, personality traits such as risk aversion, trust, and a tendency to avoid procrastination matter. The observed intention action gap can be explained by present-biased individuals who procrastinate and quickly forget to switch. Based on these findings, I suggest that simply drawing attention to information or educating consumers is unlikely to stimulate market activity. I recommend for policymakers to consider implementing smart defaults, for which I find strong citizen support in my research.​

Working paper

Do multi price offers in supermarkets increase household food waste?

with Milica Mormann

This research demonstrates how retail promotions can lead to overbuying of food items, resulting in an increase in household food waste. The results from a large-scale field experiment with the data from 40,000 perishable vegetable purchases from eight supermarkets across Sweden show that consumers exposed to multiple-unit offers (e.g., “2 for X”) purchased more compared to those exposed to a single unit discount (e.g., “1 for X/2”). A follow-up survey showed that these additional items are subsequently less likely to be consumed, leading to an increase in household food waste. The effect of multiple-unit offers on purchased quantity are reduced when the savings compared to buying one unit are made salient or when a nudge reminds consumers to consider their consumption. These results provide important insights into factors that increase food waste, and to the power of retailers to negatively, and also positively, impact important societal and environmental causes.

R&R at Scientific Reports

Peer Evaluation Tournaments

with Martin Dufwenberg and Katja Görlitz

Peer evaluation tournaments are common in academia, the arts, and corporate environments. They make use of the expert knowledge that academics or team members have in assessing their peers’ performance. However, rampant opportunities for cheating may throw a wrench in the process, unless, somehow, players have a preference for honest reporting. Building on Dufwenberg & Dufwenberg (2018)’s  theory of perceived cheating aversion, we develop a multi-player model where players balance the utility of winning against the disutility of being identified as a cheater. We derive a set of predictions, and test these in a controlled laboratory experiment.

Working paper

Nudge Me! A field experiment on reminders for medication adherence

with Kai Barron, Mette Trier Damgaard

Reminders can successfully change behavior, but have also been shown to create annoyance costs. In a field experiment with over 4000 pregnant women in South Africa, we test whether exposing women to reminders to take their prenatal supplements affects their demand for reminders through a digital health platform. We document a strong baseline demand for reminders, which increases further after exposure, despite high stated adherence. We find that pure reminders and reminders with moral suasion both increase willingness to pay for additional reminders and increase adherence, while informational reminders decrease willingness to pay and adherence.

Working paper

Time preferences and medication adherence: A field experiment with pregnant women in South Africa

with Kai Barron, Mette Trier Damgaard and Lisa Norrgren

The effectiveness of many health recommendations and treatment plans depends on the extent to which individuals follow them. For the individual, medication adherence involves an inter-temporal trade-off between expected future health benefits and immediate effort costs. Therefore examining time-preferences may help us to understand why some people fail to follow health recommendations and treatment plans. In this paper, we use a simple, unobtrusive real-effort task implemented via text message to elicit the time preferences of pregnant women in South Africa. We find evidence that both our measured discount factor and time-inconsistency are predictive of self-reported adherence to the recommendation of taking iron supplements daily during pregnancy.  This suggests that patience plays a role in determining medication adherence patterns.

Working paper

Arbitrage Or Narrow Bracketing? On Using Money to Measure Discounting

with James Andreoni, Mike Kuhn, Silvia Saccardo and Yang Yang

If experimental subjects arbitrage against market interest rates when making intertemporal allocations of cash, the data will reveal nothing about subjects’ discounting, only uncovering subjects’ market interest rates. If subjects instead frame choices narrowly, they will plan to spend cash rewards when received, implying cash has properties similar primary rewards. We test arbitrage directly by forcing all transactions with subjects to go exclusively through their financial institutions via instant electronic transfers. If subjects wish to arbitrage, this should make it as easy and salient as possible. Our evidence contradicts arbitrage, and finds evidence of present bias, supporting the view that money payments in experiments can be treated as a primary reward.

Working paper

Research visits

December 2016

Monash University

October 2016 - December 2016

University of Sydney
(visiting Robert Slonim)

April 2016

Department of Economics, University of Edinburgh
(visiting Michèle Belot)

June/July 2015

Department of Economics, University of Chicago
(visiting John List)

May 2013 - June 2013

The Becker and Friedman Institute, University of Chicago
(visiting John List)

July 2012

Center of Advanced Hinsight, Duke University
(visiting Dan Ariely)