Selected Publications

This paper investigates differences between a default, a recommendation, and a mandatory minimum contribution on private provision of a large scale public good (climate protection). Information on the regulator (neutral experimenter, expert or politician), its interaction with the intervention type, as well as with pre-intervention intrinsic motivation on voluntary contributions is analyzed. Data are from an online framed field experiment with a sample representative of the German internet using population. Main insights are: neither a recommendation nor a default close to the pre-intervention average change contributions; identifying the regulator reduces contributions when accompanying the recommendation, but not the default; contributions above the pre-intervention average are reduced by the default but increased by the mandatory minimum relative to the control; only the default negatively interacts with high intrinsic motivation; and regulator attributes neither interact with intrinsic motivation, nor with the type of intervention. The study contributes to the discussion of nudges as public policy instruments by comparing them to alternative interventions, i.e. pointing at or pushing contributions, and by shedding light on making the source of the intervention transparent.
In SSRN, 2018

Nudges receive growing attention as an effective concept to alter people’s decisions without significantly changing economic incentives or limiting options. However, being often very subtle and covert, nudges are also criticized as unethical. By not being transparent about the intention to influence individual choice they might be perceived as limiting freedom of autonomous actions and decisions. So far, empirical research on this issue is scarce. In this study, we investigate whether nudges can be made transparent without limiting their effectiveness. For this purpose we conduct a laboratory experiment where we nudge contributions to carbon emission reduction by introducing a default value. We test how different types of transparency (i.e. knowledge of the potential influence of the default, its purpose, or both) influence the effect of the default. Our findings demonstrate that the default increases contributions, and information on the potential influence, its purpose, or both combined do not significantly influence the default effect. Furthermore, we do not find evidence that psychological reactance interacts with the influence of transparency. Findings support the policy-relevant claim that nudges (in the form of defaults) can be transparent and yet effective.
Journal of Economic Psychology, 2018

Labeling news as fake is a recent phenomenon occurring predominantly online, and increasingly in political online environments. This paper investigates the influence of expressed doubt in media independence on trust in news reports on climate change, and on trust in more scientific sources. Evidence from a laboratory experiment does not suggest that reading a media-critic statement affects perceived trust in the media-, or the scientific source reporting on climate change. Bayesian analyses provide a practical interpretation of the null findings, and further analyses show that the statement decreases trust in the scientific source when subjects read the media article first. Findings add to the emerging literature on fake news, echo chambers and filter bubbles, suggesting that labeling stories or outlets as fake news may not affect public opinions. Further research is needed to substantiate this conclusion.
In SSRN, 2018

Recent Publications


Climate Debate

In this project I use text-mining procedures to understand how we discuss climate change online. I quantitatively analyse online articles on climate change, both from skeptical and affirmative standpoints.

Effects of scarcity on pro-social nudges

This project aims at mapping the potential interactions between various forms of scarcity on the performance of pro-social/ green nudges. Specifically, we use laboratory and field experiments to test whether economic, cognitive, and social scarcity change decision-makers proneness to nudges that aim to reduce negative externalities.

Green Nudging

This project evaluates the relative performance of nudges and conventional instruments to foster pro-environmental behavior.

Transparent Nudges

This project evaluates the impact of transparency on nudge-performance.

Climate Change Skepticism

This project investigates causes underlying public skepticism towards the occurence of man-made climate change, as well as differences and similarities between arguments underlying both positions.

Recent Posts

More Posts

Science is there to answer questions, and it is a powerful tool at that. In this post I outline how I approach the task of coming up with research questions, how to answer them and how to create a publishable manuscript describing this procedure. It is very idiosyncratic, but I hope that it might be useful for some readers, especially students.


For one of my projects I needed to download text from multiple websites. I did this with rvest and dplyr. While this can be relatively easy if the sources come from the same websites, it can be pretty tedious when the website hosts are various. The reason is how the content is kept in the HTML of the website. Assume that you want to extract the title, author information, publish date, and of course the main article text. You can access that information via CSS or XPath. The following text will walk you through an example and provide the relevant code.


This post will explain how to integrate RStudio and LaTeX, especially the inclusion of well-formatted tables and nice-looking graphs and figures produced in RStudio and imported to LaTeX. To follow along you will need RStudio, MS Excel and LaTeX.



Aktuelle Probleme der Umweltökonomik

University of Hamburg, Summer 2019

The Economics of Climate Change

University of Hamburg, Summer 2019

Verhaltensökonomik für die Umwelt

University of Hamburg, Fall 2018/ 2019


CorrelAid e.V.

We are a network of young data analysts that wants to change the world with a more inclusive, integrated and innovative approach to data analysis. CorrelAid builds on three pillars: We take a pioneer role in analytics consulting for Non-Profit-Organisations. We connect young, driven data scientists and offer them the possability to apply and develop their skills on real-world problems. Last but not least, we start a dialogue on the potential of data and analytics for the civic society.

Seehilfe e.V.

Projekt Seehilfe e.V. aims on a long-term basis to strengthen integrative and educational structures for refugees arriving in Europe by providing workshops and general recreational offerings, as well as administrational and bureaucratic support, especially in Sicily.


This blog submits part of its posts to R-Bloggers.