ISSN (Print) 0473-453X

Discussion Paper No. 1228

ISSN (Online) 2435-0982

HOW TO INCREASE PUBLIC SUPPORTFOR CARBON PRICING

Andrej Woerner
Taisuke ImaiDavide D. Pace
Klaus M. Schmidt

December 2023

The Institute of Social and Economic Research
Osaka University
6-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

How to Increase Public Support for Carbon Pricing ∗Andrej Woerner1,3

Taisuke Imai2,3Davide D. Pace1,3Klaus M. Schmidt1,3,4,*

1 Department of Economics, LMU Munich
2 Institute of Social and Economic Research, Osaka University
3 CESifo
4 CEPR* To whom correspondence should be addressed. E-mail: klaus.schmidt@lmu.de

December 21, 2023

Abstract
The public acceptability of a carbon price depends on how the revenues from carbon pricing are used. In a fully incentivised experiment with a large representative sample of theGerman population, we compare five different revenue recycling schemes and show that
support for a carbon price is maximised by a “Climate Premium” that pays a fixed, uniform, upfront payment to each person. This recycling scheme receives more support thantax and dividend schemes, than using revenues for the general budget of the government,
and than earmarking revenues for environmental projects. Furthermore, we show thatparticipants and experts underestimate the public support for carbon pricing.

∗ We thank Louis Cho, Michael Maurer-Hernandez, Andrey Samarskiy, and Philippa von Wedel for their re-search assistance. We are grateful for the feedback from Peter Andre, John Duffy, Simeon Schudy, and the audience at Venice Summer Institute 2023 and IESEG workshop on the Psychology and Economics of Climate Policy.
We thank the Deutsche Forschungsgemeinschaft (DFG, Project-ID 280092119, TRR 190) and JSPS KAKENHI (No.
JP22K21358) for financial support.

1

1

Introduction

Many policymakers have tried and failed to implement carbon pricing. In Switzerland, a proposal to increase an existing carbon price did not succeed in a popular vote in 2021; in France,
the yellow vest movement forced President Macron to withdraw a carbon tax on fossil fuels;in the US, carbon pricing is so unpopular that none of the major political parties embraces it.
Overall, only 23% of global greenhouse gas emissions are subject to carbon pricing 1 .
There are several reasons for popular resistance. Some voters do not trust the governmentand believe that a carbon price is just a disguised tax increase 2,3 . Others feel that carbon
pricing is unjust because it disproportionately hurts the poor 4,5 . Many people see that they
have to pay more, but they do not see the benefits in terms of reduced emissions and tax
revenues that can be used for other beneficial purposes 6,7 . Can smart carbon pricing addressthese concerns and gain more public support?
Previous research has shown that specific uses of the revenue can increase public support for carbon pricing 8,9 , in particular earmarking revenues for green investments or energy
efficiency programmes 10 , and returning revenues to citizens (“tax and dividend”) 8,11–13 . However, this literature is inconclusive in which revenue recycling scheme receives the most public
support.
This paper makes three contributions. First, it shows experimentally that public support
for a carbon price is maximised by a “Climate Premium” that compensates citizens at the time
when the carbon price is introduced with a fixed payment equal to the expected revenues fromcarbon pricing 14 . This scheme not only makes it salient that carbon pricing is not a disguised
tax increase, it also eliminates any uncertainty about the amount people will receive. Such ascheme has been implemented successfully in Austria in 2022.
Second, in contrast to previous analyses, our study is based on a fully incentivised experiment with a large, representative sample of the German population. In the experiment,
subjects make purchase decisions that result in real carbon emissions, and they have to pay
a real carbon price of e 50 per ton of CO2 . We consider five conditions that differ in how
the revenues from carbon pricing are used. We measure public support by letting people
vote on the introduction of carbon pricing. Our design combines the best aspects of and improves upon both surveys and laboratory experiments, the two methods commonly used to
study support for climate policy 8,15–26 . Surveys often use representative samples, but they are
not incentivised and have been shown to overestimate public support for pro-environmental
policies 27 . In contrast, our design uses monetary incentives to elicit participants’ true preferences. Laboratory studies, instead, are usually incentivised, but they rely on small andnon-representative samples (often undergraduates) and use experimental designs in which
externalities are imposed on other experimental participants but not on the environment. In
contrast, our experiment uses CO2 emissions as externalities and a representative sample ofthe population.
2

Third, our innovative methodology can uncover misperceptions about the effectiveness ofthe carbon price in reducing consumption and about the public support for carbon pricing.
Beliefs about the policies’ effectiveness to curb climate change have a strong impact on voters’
support 22 , but there is only indirect and mixed evidence on how people expect others to adjust
consumption following the implementation of a carbon price 21,28 . Furthermore, by conducting
an expert survey in which 369 experts predict the outcome of the experiment, we show thatexperts strongly underestimate the public support for smart carbon pricing schemes.

2

Results

We conducted an experiment with 1,100 participants who are representative of the German
population in terms of gender, age (older than 18 years old), income, education, and regionof residence. Participants had to make two purchase decisions about a valuable but CO2 generating product. The first decision involved a low price per unit, while the second decision
had an additional carbon price (e 50 per ton). Following these decisions, the participants
voted to determine whether to implement the purchase decision with or without the carbon
price. Importantly, all decisions in the experiment have real consequences. The participants’purchase decisions resulted in monetary payoffs and real CO2 emissions. By voting, eachparticipant had an equal chance to determine whether purchase decisions with or without acarbon price were relevant to their own and other participants’ payoffs.
In five within-subject conditions, the participants voted on whether or not to implement
carbon pricing schemes that differed in how revenues from carbon pricing were used. In the“State Budget” condition, the money went to the general budget of the German federal government. In the “Climate Projects” condition, the revenues were spent on government-approved
environmental projects. The “Redistribute All” and “Redistribute Poor” conditions mimicked“tax and dividend” schemes: the revenues were divided equally either among all participants
or among those participants who had reported an income below e 2,100 (median income). In
the “Climate Premium” condition, participants were promised a fixed and immediate payment
in case the carbon price was implemented. In two between-subjects treatments, we used either a e 1.40 or a e 1.70 premium, both of which are somewhat lower than the actual revenue
per head generated by the carbon price.
Finally, we conducted an expert survey (𝑁 = 369) with environmental, behavioural, andpublic economists working in Germany, Austria, and Switzerland (response rate 28.0%). We
asked these experts to estimate the purchase decisions and the vote shares for carbon pricing
in the different conditions.

3

a

c

Without carbon price

2 units€0
CO2 120kg

Frequency

0.6
2 units€6
CO2 120kg

0.4

0.2

1 unit€1
CO2 60kg

0.0
0 units€0
CO2 0kgb

1 unit€4
CO2 60kg

2 units€6
CO2 120kg

1 unit€4
CO2 60kg

With carbon price

Frequency

0.6

0.4
0 units€0
CO2 0kg

0.2

0 units€0
CO2 0kg

0.0
0 units€0
CO2 0kg

1 unit€1
CO2 60kg

2 units€0
CO2 120kg

Without
carbon priceWith
carbon priceFig. 1: Purchase decisions. (a) Scenario when the price of each product was e 3 (without carbon price).
(b) Scenario when the price of each product was increased e 6 (with a carbon price). (c) A Sankey
diagram representing participants’ responses to a price increase.

2.1

Buying behaviour

Fig. 1a illustrates the distribution of purchase decisions without a carbon price. Although it isprofitable to buy both products, only 34.3% of our sample do so, suggesting that many participants are foregoing private gains for the sake of the environment. This result suggests thatthe participants expect their decisions to affect real CO2 emissions. Indeed, 77.9% explicitly
confirm that they believe that their purchases reduce the number of offsets bought by theexperimenter (as described in the instructions). Fig. 1b shows a sharp and significant drop in
the number of units bought when the carbon price is introduced and that CO2 emissions are
reduced significantly (units purchased per person: 1.06 without carbon price and 0.60 without;𝑡 (1099) = 24.10; 𝑝 < 0.001). The figure also shows that, when there is a carbon price, very few
subjects (2.9%) buy two products, a dominated choice because people do not earn anythingfrom this decision, but they emit 120kg of CO2 . Fig. 1c depicts how participants adapt theirconsumption with the introduction of a carbon price. Only very few subjects (2.8%) purchasemore products with than without the carbon price. These low numbers suggest that almost
all the participants understand the experiment.aa See Supplementary Methods for additional information regarding the measures taken to ensure data quality.

We also show that the results remain unaffected by variations in task comprehension or attentiveness levels.

4

Share in favour of carbon price

1.00

0.75

0.50

0.25

0.00
State
BudgetClimateProjects

Redistribute Redistribute
Poor
All

ClimatePremium

Fig. 2: Share of participants voting in favour of a carbon price under five revenue recycling schemes.
The bars indicate 95% CI.

2.2

Voting behaviour

Fig. 2 displays the voting decisions.b There is substantial heterogeneity in support dependingon the revenue recycling scheme. When revenues go to the general budget of the federal
government, a minority of participants votes for carbon pricing (47.3%). This is reflected inreported low trust in the government: 52.5% (21.5%) disagreed (agreed) with the statement “Ihave confidence in the German government to use taxpayers’ money wisely.”
However, the majority approves the carbon price under the other revenue recycling schemes.
In conditions Climate Projects and Redistribute Poor, 62.6% and 62.7% of the votes are infavour of the carbon price. This percentage grows to 68.8% in the Redistribute All condition
and further jumps to 73.1% in the Climate Premium condition. All of these schemes receive
significantly more than 50% of the votes (𝑝 < 0.001). Interestingly, Redistribute All fares better than Redistribute Poor, because richer participants are significantly less likely to vote infavour of the latter (54.5% vs. 68.8%; 𝑧 = 6.63; 𝑝 < 0.001) while poorer participants support
both schemes similarly (70.6% vs. 68.8%; 𝑧 = 1.09; 𝑝 = 0.275). The share of votes in favourof the Climate Premium is significantly higher than for any other scheme (vs. State Budget𝑧 = 14.84, vs. Climate Projects 𝑧 = 7.35, vs. Redistribute Poor 𝑧 = 7.55, vs. Redistribute All𝑧 = 3.49; all 𝑝 < 0.01 with Bonferroni correction). These results are not affected by the orderof presentation of the five schemes (Supplementary Figure 6).
Overall, these results show that the Climate Premium is the most popular scheme, andthey confirm that revenue recycling is an effective lever to increase support for carbon prices.
Choosing the right mechanism can increase support by more than 25 percentage points.
b Supplementary Table 4 shows which demographic characteristics are predictive of overall voting behaviour.

5No carbon priceState Budget

0.4
0.2
0.0

0.4
0.2
0.0

0.4
0.2
0.0

1 2 3 4 5 6

1 2 3 4 5 6

1 2 3 4 5 6Redistribute Poor

Redistribute All

Climate Premium

0.4
0.2
0.0

0.6

Frequency

0.6

Frequency

0.6

Frequency

0.6

Frequency

0.6

Frequency

Frequency

0.6

Climate Projects

0.4
0.2
0.0

1 2 3 4 5 6

0.4
0.2
0.0

1 2 3 4 5 6

1 2 3 4 5 6

Fig. 3: Ranking of the five revenue recycling schemes and “No carbon price,” from 1 (the most preferred)
to 6 (the least preferred). See Supplementary Methods for the construction of the variable.

2.3

Other desirable properties of a Climate Premium

In this section, we show that the Climate Premium is budget-friendly, it receives majority
support among all demographic groups, and it is the proposal that the fewest number of participants consider to be the worst policy.
First, the Climate Premium is budget-friendly. In the e 1.70 treatment, the premium wascalibrated such that the total transfer was expected to be similar to the carbon pricing revenues. The calibration was successful: revenues turned out to be e 1.78 per person (𝑆𝐷 = 1.64,
95% CI [1.687, 1.881]). However, we also conducted a much more conservative e 1.40 treatment in order to test whether the support is sensitive to the amount of the premium. This is
not the case: Even with the reduced premium, the Climate Premium scheme receives more
votes than any other revenue recycling mechanism (vs. State Budget 𝑧 = 9.87, vs. Climate
project 𝑧 = 5.08, vs. Redistribute Poor 𝑧 = 5.72, vs. Redistribute All 𝑧 = 3.03; all 𝑝 < 0.05
with Bonferroni correction; Supplementary Figure 4). Furthermore, there is no significant
difference between support for the Climate Premium with a e 1.40 and e 1.70 payment (74.0%
vs. 72.2%; 𝑧 = 0.68; 95% CI [−0.034, 0.071]; 𝑝 = 0.497). Hence, the Climate Premium can bebudget-friendly without compromising support.
Second, the popularity of the Climate Premium is not specific to one particular group of
voters. Supplementary Figure 5 and Supplementary Table 3 show that the Climate Premium
receives majority support in all demographic groups, including among conservatives (58.8%)
and people who self-report that they are not much concerned about climate change (51.3%).
Hence, the Climate Premium seems acceptable to a wide range of demographic groups andpolitical parties, a property that it shares only with the Redistribute All condition.
6

Purchased units

1.5

1.0
ActualBelief (participants)
Belief (experts)
0.5

0.0
Without carbon priceWith carbon priceFig. 4: Actual and guessed number of products purchased. The bars indicate 95% CI.

Finally, it is more difficult to implement a policy that is strongly opposed by some minority
groups. In fact, there is recent evidence that politicians prefer policies that few people see as
the worst possible option 29 . Fig. 3 shows that only 4.2% of the subjects consider the Climate
Premium the worst policy. This number is significantly lower than the corresponding sharesfor State Budget (37.2%), Climate Projects (10.6%), and Redistribute Poor (9.1%) and insignificantly so for Redistribute All (5.2%). The number is also significantly lower than the share of
subjects who consider no carbon price as the worst option (33.7%). While very few subjects
consider the Climate Premium the worst option, there are also only few subjects (17.2%) for
whom it is their most preferred. Instead, most subjects give it a medium rank. Compared toother schemes, in particular Climate Projects, the Climate Premium is thus not as polarising.
This result suggests that the Climate Premium could be a compromise solution that enables
the implementation of a carbon price.

2.4

Misperceptions

Voting decisions are affected by expectations about the behaviour of others 6 . In our experiment, the decision to vote for a carbon price depends on the belief on how this price will affectthe purchasing behaviour of all other subjects: The change in behaviour will affect the amountof carbon emissions and revenues. Therefore, we elicited the participants’ beliefs about how
many units are bought with and without the carbon price. We also elicited subjects’ beliefs
about the voting results in different conditions.
Beliefs about buying behaviour. The participants significantly underestimated the effectof the carbon price on buying behaviour. Fig. 4 shows that, on average, participants believethat the carbon price reduces purchases by 0.17 units (𝑆𝐷 = 0.41), significantly less than theactual drop of 0.47 units (𝑡 (1099) = −13.56; 95% CI [−0.338, −0.252]; 𝑝 < 0.001) which is morethan 2.5 times larger. This misperception is important because beliefs about the effectivenessof climate policy are a key driver of public support 22 .
7

Share in favour of carbon price

1.00

Actual share
Belief (participants)
Belief (experts)

0.75

0.50

0.25

0.00
State
BudgetClimateProjects

Redistribute Redistribute
Poor
All

ClimatePremium

Fig. 5: Actual and guessed shares of participants voting in favour of carbon price. The bars indicate
95% CI.

Furthermore, the same Fig. 4 shows that the participants overestimate the number of units
bought when the carbon price is in place. Participants buy only 0.59 units on average, but they
believe that the number is 1.07, almost twice as high. This misperception makes it unlikelythat the participants voted in favour of the Climate Premium because they mistakenly believed they would receive a higher payment in the Climate Premium than in the Redistribute
All condition. Such a belief would have arisen if the participants had underestimated theconsumption with the carbon price.
These misperceptions are consistent with previous evidence that individuals ignore theeffect of taxes on prices 30 and underestimate other people’s behavioural responses to policychanges 6 .
Beliefs about voting behaviour. Fig. 5 shows that participants strongly and significantly
underestimate the support for carbon pricing, regardless of the revenue recycling scheme. Averaged over all conditions, they predict 42.7% instead of 62.9% of votes in favour of the carbon
price. The underestimation is especially large in the State Budget (26.5 percentage points) andClimate Premium (23.2 percentage points) conditions. Other studies have shown that correcting similar misperceptions raises individual willingness to act against climate change as wellas support for climate policies 31,32 .

2.5

Expert Predictions

In contrast to the participants, the experts did not underestimate the effect of the carbon
price on consumption (Fig. 4). On average, they predict that the carbon price results in adrop of 0.52 units, which is not significantly different from the actual drop of 0.47 (𝑡 (1032) =8

1.691; 95% CI [−0.008, 0.104]; 𝑝 = 0.091). However, experts significantly underestimate thesupport for carbon pricing. Averaged over all conditions, experts expect that 45.4% of votes
are in favour, while the actual number is 62.9%. Importantly, the experts mistakenly predictthat the Redistribute All condition and not the Climate Premium is the policy receiving thehighest support (56.5% vs. 49.2%; 𝑡 (368) = 6.569, 95% CI [0.051, 0.094]; 𝑝 < 0.001). Hence, theeconomics profession is too pessimistic about the public support for a smart carbon pricing
scheme and holds mistaken beliefs about which scheme is the most popular.

3

Discussion

The literature on the public support for carbon pricing has so far relied either on unincentivised surveys or on experiments with non-representative subjects. This study combinesthese two approaches in a fully incentivised representative survey experiment, which has
several advantages. First, it provides financial incentives for the participants to truthfully
report their preferences for carbon taxes. This feature mitigates concerns that participants’
responses are influenced by image concerns and desirability bias, which might artificially inflate the stated support for carbon pricing. The presence of incentives is particularly important
if different revenue recycling schemes are compared. In fact, previous evidence indicates thatthe magnitude of the bias in survey responses varies with the type of policy the participants
have to opine upon 27 .
Second, in the experiment, consumption and voting decisions result in real CO2 emissions, while most other experiments on climate policies rely on monetary externalities on
fellow subjects. In our setting, less consumption results in lower CO2 emissions, which has anegligible effect on the climate. This is also true if a small country (such as Germany) reduces
its carbon emissions.
Third, our experiment uses a representative sample of the population. Thus, the results
are not biased by a selective subject pool, such as the young, well-educated, and mostly liberal
undergraduate students that are typically used in economic experiments.
The results show that support for carbon pricing is maximised if revenues are redistributed
as a Climate Premium: a salient, upfront, fixed, and equal payment. The Climate Premium
outperforms the revenue recycling schemes that have been more commonly studied, suchas tax and dividend schemes and schemes that use tax revenues to finance environmental
projects or go to the general budget. In addition, the Climate Premium has several properties
that make it appealing to policymakers: it is budget-friendly, it achieves majority support inall demographic groups, and it is the policy that is rated the least preferred by the fewest
people. Our results contrast with expert predictions. Experts expected the tax and dividend
schemes to fare better than the Climate Premium. Moreover, they generally underestimate
the support for carbon pricing.
The experiment provides additional support for important earlier findings. First, it con9

firms that revenue recycling is a strong driver of support for carbon pricing. Second, it confirms that people underestimate the support of others for costly climate policies. Third, itshows that people underestimate the effectiveness of carbon taxes in reducing emissions.
These three results appear to be robust to an array of different research designs.

4

Methods

The experiment was carried out in June 2023 in collaboration with Bilendi (www.bilendi.
co.uk), a market research company specialising in online surveys with proprietary panels
in several European countries. There were 1,100 participants representative of the German
population (see Supplementary Table 1 for a summary of demographic characteristics). The
instructions, available in Supplementary Information C, utilised straightforward language,
visual aids, comprehension questions, and attention checks, to ensure that participants understood the procedures.
Participants could buy zero, one, or two fictitious products. The first product had a valueof e 7, the second a value of e 5. Participants could buy the second product only if theybought the first. The purchase of each product resulted in the emission of 60kg of CO2 (seebelow). In the first decision, each product had a price of e 3. Thus, participants earned e 4
if they bought one product (7 − 3) and e 6 if they bought two (7 + 5 − 3 − 3). In the second
decision, the price of each product increased to e 6. Consequently, participants earned e 1 forpurchasing one product (7 − 6) but nothing for buying both (7 + 5 − 6 − 6). This price increase
mirrors the effect of a carbon price of e 50 per ton of CO2 . At this stage, participants did notknow that the price increase was due to a carbon price.
Decisions had real-world consequences. The payment received by each participant at theend of the experiment and the amount of CO2 emissions depended on the number of products
they bought and on which of the two decisions was implemented at the voting stage. We committed to buy offsets from Carbonfund.org for 60kg of CO2 for each product not purchased.
Hence, the number of offsets was reduced by 60kg of CO2 each time a participant decided
to buy a product, effectively increasing total CO2 emissions by this amount 33 . Participants
were sent proof of purchase for the offsets after all data had been collected (Supplementary
Methods).
Participants had been informed that they were part of a group of 50 individuals drawn froma representative sample of the German population and that the vote of one randomly selectedgroup member determined which of the two purchase decisions would be implemented forthe entire group. This procedure, called “random dictator” in the experimental economics
literature, ensured that each participant had an equal probability of deciding the outcome ofthe vote for the whole group (including themselves). With this procedure, participants havean incentive to vote according to their true preferences (truth-telling is a dominant strategy).
At the voting stage, participants voted in five distinct conditions that differed in how the10

revenues from carbon pricing were used. Every participant encountered all conditions in random order, knowing that one of them would be randomly chosen to determine their payoffs(Supplementary Table 2). In the “State Budget” condition, the revenues went to the German
federal government.c In the “Climate Projects” condition, the revenues were given to a German organisation supported by the German National Climate Protection Initiative (Nationale
Klimaschutzinitiative; https://www.klimaschutz.de). In the “Redistribute All” condition,
each group member received an equal share of the carbon price revenues. In the “RedistributePoor” condition, revenues were evenly divided among group members with a monthly income below e 2,100, the median income in our sample.d In both the Redistribute All and theRedistribute Poor conditions, the money was transferred to the participants two weeks after
the completion of the experiment. In the “Climate Premium” condition, participants were
given a fixed payment if the carbon price was implemented. The payment was either e 1.40
or e 1.70 with 550 participants in each treatment. These payments were made within twodays of participation in the experiment.
Finally, participants were asked to answer survey questions. First, they ranked the five different revenue recycling schemes. Then, they reported their beliefs about the purchasing andvoting behaviour of the other group members. These belief elicitations were incentivised withe 10 for the correct prediction of one randomly selected question, an incentive-compatible beliefs elicitation procedure 34 . Finally, participants answered questions about their time and risk
preferences as well as their political preferences.
For the expert survey, we contacted 1,318 academic economists, of which 481 started thesurvey, and 369 completed it and are in our data. Experts were shown a simplified versionof the instructions and asked to predict the purchase and voting decisions. They could earn
e 40 if their estimate in a randomly chosen prediction question was at most two percentage
points below or above the actual percentage. The instructions are available in Supplementary
Information C.
Further details on methods can be found in the Supplementary Methods.

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[32] Fang, X. & Innocenti, S. Increasing the acceptability of carbon taxation: The role of social
norms and economic reasoning (2023). INET Oxford Working Paper No. 2023-25.
[33] Pace, D., Imai, T., Schwardmann, P. & van der Weele, J. Uncertainty about carbon impact
and the willingness to avoid CO2 emissions (2023). CRC TRR 190 Discussion Paper No.
470.
[34] Schlag, K. & Tremewan, J. Simple belief elicitation: An experimental evaluation. Journalof Risk and Uncertainty 62, 137–155 (2021).

13

Supplementary Information

How to Increase Public Support for Carbon Pricing
Andrej Woerner

Taisuke ImaiDavide D. Pace

Klaus M. Schmidt

Contents
A Supplementary Methods
A.1 Main Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A.2 Expert Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1
1
6

B Supplementary Results

8

C Instructions and the Interface
15
C.1 Main Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
C.2 Expert Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
References

56

A

Supplementary Methods

A.1

Main Experiment

A.1.1

Data quality

We took great care to ensure the comprehensibility of the experiment for all participants,
including those with lower educational backgrounds. To achieve this objective, we divided theexperiment into four sections, each accompanied by its instructions. We minimised textual
content, employed simplified language, and incorporated visual aids extensively to explain
the consequences of each possible decision. Additionally, we presented 12 comprehension
questions organised into eight sets. Participants were required to provide accurate responses
to all questions before advancing in the experiment. Finally, during the consumption decision
with the carbon tax, participants were asked to confirm their choice in case they opted to buy
both products. The prompt stated:“Are you sure you want to buy both products? Please note: The additional purchase of Product BLUE will reduce your payout and increase CO2 emissions.”
We implemented this prompt because buying two products under the tax is most likely due
to confusion. In any case, the participants could confirm their choice and buy both products
if so they wished. The English translation of the instructions, along with the experimentinterfaces, is available in Supplementary Information C.1.
To screen out the participants who were not fully engaged, we incorporated an attention
check on the first page of the experiment. Participants who did not pass this check were notallowed to participate in the experiment. Additionally, a second attention check was introduced in the final questionnaire. In this case, participants who failed it were still allowed tocomplete the experiment.
A.1.2

Ranking

In the final phase of the experiment, participants were asked to order five revenue recycling
schemes, from the most preferred (1) to the least preferred (5). We combine this ordinal data(⪰𝑜 ) with participants’ voting decisions to construct a variable capturing the “ranking” (⪰𝑟 )of the five schemes and the baseline of “No carbon price.”
Given a participant’s ordering data, schemes that received positive votes are placed above,
while those that received negative votes are placed below the “No carbon price” baseline. The
participant’s original ordering is respected within each category.
This rule implies that the “No carbon price” baseline would be ranked “the most preferred”(“the least preferred”) scheme if a participant voted against (in favour of) all five recycling
schemes.

1For example, suppose a participant voted in favour of schemes 𝑆 1 , 𝑆 2 , and 𝑆 3 , and against
schemes 𝑆 4 and 𝑆 5 . Suppose also that the participant ordered them 𝑆 2 ⪰𝑜 𝑆 4 ⪰𝑜 𝑆 1 ⪰𝑜 𝑆 5 ⪰𝑜 𝑆 3
in the questionnaire. Then, we assign a ranking of 𝑆 2 ⪰𝑟 𝑆 1 ⪰𝑟 𝑆 3 ⪰𝑟 𝑆 0 ⪰𝑟 𝑆 4 ⪰𝑟 𝑆 5 to thisparticipant, where 𝑆 0 indicates the baseline, “No carbon price.”
A.1.3

Robustness

The main qualitative results regarding purchase and voting decisions remain after excluding
participants who exhibit signs of confusion or inattentiveness. In Supplementary Figure 7, welook at average units purchased (panel a) and support for revenue recycling schemes (panel b)in four subsamples of participants:• Sample 1 excludes participants who did not believe that their purchases would reduce
the number of offsets bought by the experimenter.
• Sample 2 excludes participants who were unable to provide correct answers on the firstattempt in three or more out of the 12 comprehension questions.
• Sample 3 excludes participants who failed the second attention check in the final questionnaire.
• Sample 4 applies all the exclusion criteria above.
The patterns are not affected by the level of understanding of the task or the attentiveness.

2A.1.4

Preregistration

CONFIDENTIAL - FOR PEER-REVIEW ONLY
Public Support for Carbon Pricing (#134346)
Created: 06/02/2023 07:21 AM (PT)This is an anonymized copy (without author names) of the pre-registration. It was created by the author(s) to use during peer-review.
A non-anonymized version (containing author names) should be made available by the authors when the work it supports is made public.

1) Have any data been collected for this study already?
No, no data have been collected for this study yet.
2) What's the main question being asked or hypothesis being tested in this study?
We investigate which forms of redistribution schemes attract stronger support for carbon pricing from an approximately representative sample (in gender,
age, region of residence, and income) of the German population.
3) Describe the key dependent variable(s) specifying how they will be measured.
The key dependent variable is the binary voting decision indicating the participant's attitude toward carbon pricing (1: in favor; 0: against).
Participants can buy up to 2 units of a virtual product. Buying the product is profitable but the consumption of each unit leads to CO2 emissions. Eachparticipant decides how many units to buy, without and with a carbon price. They are then matched into groups of 50 and vote on whether to implement
the decision with the carbon price or the one without it. They make 5 voting decisions as described below.
4) How many and which conditions will participants be assigned to?
All participants will make 5 voting decisions (in random order), which differ in the way the revenue from the carbon price will be redistributed. The 5
redistribution schemes are:[A] The revenue accrues to the budget of the federal government.
[B] The revenue from a group of 50 participants is redistributed equally among all the group members.
[C] The participants receive a fixed monetary transfer independent of the amount of tax revenue coming from the group.
[D] The revenue from a group is redistributed equally among low-income members of the group.
[E] The revenue is donated to climate projects supported by the German government.
There will be 2 between-subject conditions, which differ in the size of the lump-sum climate premium in policy [C]: 1.70 euros in condition 1 and 1.40 euros
in condition 2.
5) Specify exactly which analyses you will conduct to examine the main question/hypothesis.
We will regress voting decisions on dummies for redistribution schemes, without and with demographic controls such as age, gender, income, etc. The
main specification will pool the 2 between-subject conditions in policy [C].
6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations.
There will not be any outliers. We will conduct additional analyses to test whether performance in the comprehension questions as well as the second
attention check question is related to voting and buying behavior.
7) How many observations will be collected or what will determine sample size? No need to justify decision, but be precise about exactly how thenumber will be determined.
We aim at collecting 1100 observations, 550 in each condition. This number was determined based on pilot data with 100 participants and power
calculations (allowing us to detect about a 4 percentage point difference in support with 80% power). The pilot data was used solely for the calibration ofexperimental parameters and will not be included in the analysis.
8) Anything else you would like to pre-register? (e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?)
We will correlate voting decisions with buying decisions and demographics as well as beliefs and personal characteristics, such as political orientation,
climate attitudes, and economic preferences (risk and time), that we elicit in the post-experimental questionnaire.
We will conduct additional analyses to test whether performance in the comprehension questions and the second attention question is related to buying
and voting decisions.
Finally, we will conduct a forecasting survey with German-based researchers in the fields of behavioral, environmental, and public economics.

Version of AsPredicted Questions: 2.00

Available at https://aspredicted.org/VKZ_4QX

3

A.1.5

Carbon offset certificate and invoice

LMU München - Experiment96 Tonne(s) of CO2
07/10/2023

Supplementary Figure 1: Certificate.

4Supplementary Figure 2: Invoice.

5

A.2

Expert Survey

We manually assembled a list of economists working in the fields of environmental, public,
and behavioural economics, with a particular focus on economists working in Germany, Austria, and Switzerland. More precisely, our research assistants were instructed to:
1. find a list of all German, Austrian, and German-speaking Swiss universities (no Fachhchschulen) and of all Economic Research Institutes (restrict attention to “Leibniz Institute”),
2. go to the websites of the Economics departments of all German-speaking universities
and look for chairs on relevant topics (e.g., Environmental Economics, Energy Economics, Resource Economics, Public Economics, Fiscal Economics, Economics of Taxation, Experimental Economics, Behavioural Economics), and
3. include all the members working at these research groups: Professors, Assistant Professors and Postdocs, and Ph.D. students.
The list, assembled in May 2023, includes 1,318 academic economists. We call them “experts.” We invited these 1,318 experts to participate in our survey (Supplementary Figure 3),of which 481 started and 369 completed. See Supplementary Table 5 for the demographic
characteristics of the experts.
The structure of the survey was identical to the main experiment. After reading a simplified version of the instructions (Supplementary Information C.2), experts were asked to maketwo purchase decisions and five voting decisions. Importantly, these decisions were hypothetical and had no material consequences. The purpose of the purchasing and voting stages
was to make experts familiarise themselves with the environment of the main experiment.
Note also that the experts were randomly assigned to a e 1.40 or a e 1.70 Climate Premium
treatment, as in the main experiment.
We elicited the experts’ predictions regarding the behaviour, two purchase decisions andfive voting decisions, of the 1,100 participants in the main experiment. The experts could earn
e 40 if their estimate in a randomly chosen prediction question were at most two percentage
points below or above the actual percentage. Seventeen experts were entitled to the bonus,
but three were not paid out since they did not provide their contact information.

6

Dear [expert’s name],Our research group at LMU Munich has conducted a representative study on the German population’s approval of different variants of CO2 pricing.
We are now interested in what experts like you expect the population to think about
this issue. We are therefore asking you for your assessment.
It will take about 10 minutes to answer our questions. If your expectations are correct,
you could win a prize of 40 euros.
Here is the link to the survey.
[Link to the survey]
Have fun and thank you very much! We look forward to hearing your opinion.
Best regards,
Klaus M. Schmidt
Supplementary Figure 3: Invitation to the prediction survey sent to the experts.

7

B

Supplementary Results
Climate premium

Share in favour of carbon price

1.00

€1.40

€1.70

0.75

0.50

0.25

0.00
State
BudgetClimateProjects

Redistribute Redistribute
Poor
All

ClimatePremium

Supplementary Figure 4: No effects of the size of Climate Premium on policy support. Notes: The bars
indicate 95% CI.

GenderMale

Female

0.75

0.50

0.25

0.00
ClimateProjects

Redistribute Redistribute
Poor
All

ClimatePremium

Below €2,100

Above €2,100

Income1963-1982

1983-

0.75

0.50

0.25

State
Budget1.00

Share in favour of carbon price

1.00

Share in favour of carbon price

-1962

0.00
State
Budget

0.75

0.50

0.25

0.00

ClimateProjects

Redistribute Redistribute
PoorAll
Conservative

Political orientation

ClimatePremium

NeutralLiberal

0.75

0.50

0.25

0.00
State
BudgetClimateProjects

Redistribute Redistribute
Poor
All

Climate concern

ClimatePremium
Low

State
Budget

High

0.75

0.50

0.25

0.00

ClimateProjects

Redistribute Redistribute
Poor
All

Trust in government

1.00

Share in favour of carbon price

1.00

Share in favour of carbon price

Birth year

1.00

Share in favour of carbon price

Share in favour of carbon price1.00

ClimatePremium
Low

High

0.75

0.50

0.25

0.00
State
BudgetClimateProjects

Redistribute Redistribute
Poor
All

ClimatePremiumState
BudgetClimateProjects

Redistribute Redistribute
Poor
All

ClimatePremium

Supplementary Figure 5: Heterogeneity in policy support. Notes: The bars indicate 95% CI.

8

Task order

1

2

3

4

5 b 1.00

Share in favour of carbon price

Share in favour of carbon pricea 1.00

0.75

0.50

0.25

0.00

After "State Budget"

No

Yes

0.75

0.50

0.25

0.00
State
BudgetClimateProjects

Redistribute Redistribute
Poor
All

ClimatePremium

ClimateProjects

Redistribute
Poor

Redistribute
All

ClimatePremium

Supplementary Figure 6: Irrelevance of the order of presentation.

Purchased units

1.5

1.0

All (1100)
Sample 1 (857)
Sample 2 (874)Sample 3 (1006)
Sample 4 (672)

0.5

0.0

Share in favour of carbon priceWithout carbon priceWith carbon price

1.00

0.75
All (1100)
Sample 1 (857)
Sample 2 (874)Sample 3 (1006)
Sample 4 (672)

0.50

0.25

0.00
State
BudgetClimate RedistributeRedistribute Climate
Projects
Poor
All
Premium

Supplementary Figure 7: Purchase and voting decisions by the degree of understanding and attentiveness. Notes: Sample 1 excludes participants who did not believe that their purchases would reduce thenumber of offsets bought by the experimenter. Sample 2 excludes participants who were unable toprovide correct answers on the first attempt in three or more out of the 12 comprehension questions.
Sample 3 excludes participants who failed the second attention check in the final questionnaire. Sample 4 applies all the exclusion criteria above.

9

Supplementary Table 1: Demographic characteristics (main experiment).

Premium𝑁All

e 1.40 e 1.70

Birth year
19831963-1982-1962

384 0.349
384 0.349
332 0.302

0.351
0.329
0.320

0.347
0.369
0.284

𝜒 2 (2) = 2.48
𝑝 = 0.29

GenderFemaleMale553 0.504
545 0.496

0.491
0.509

0.516
0.484

𝜒 2 (1) = 0.62
𝑝 = 0.432

Education level1
2
3
4

329 0.371
336 0.379
198 0.223
23 0.026

0.380
0.366
0.227
0.027

0.363
0.392
0.220
0.024

𝜒 2 (3) = 1.5
𝑝 = 0.682

Income below e2,100
No
Yes

536
564

0.487
0.513

0.498
0.502

0.476
0.524

𝜒 2 (1) = 0.44
𝑝 = 0.507

Party
AfD
CDU/CSUDie Gruenen
Die Linke
FDP
SPD

183
288
165
100
111
253

0.166
0.262
0.150
0.091
0.101
0.230

0.156
0.282
0.136
0.076
0.113
0.236

0.176
0.242
0.164
0.105
0.089
0.224

𝜒 2 (5) = 7.98
𝑝 = 0.157

Political orientation
Conservative
50 0.045
Somewhat conservative 132 0.120
Neutral
531 0.483
Somewhat liberal
272 0.247
Liberal
115 0.105

0.045
0.140
0.462
0.255
0.098

0.045
0.100
0.504
0.240
0.111

𝜒 2 (4) = 5.32
𝑝 = 0.256

Big city
No
Yes
N/A

421 0.383
654 0.595
25 0.023

0.384
0.595
0.022

0.382
0.595
0.024

𝜒 2 (2) = 0.04
𝑝 = 0.979

Former East GermanyNoYes

933 0.848
167 0.152

0.869
0.131

0.827
0.173

𝜒 2 (1) = 3.42
𝑝 = 0.065

Notes: Education level: 1 (No secondary school certificate or Basic secondary school certificate), 2 (Intermediate
secondary school certificate or Other), 3 (Higher education entrance qualification), 4 (Bachelor’s/Master’s degree orDoctorate/Ph.D.). A city is classified as big city if it has more than 100,000 inhabitants, based on the data fromthe Federal Office of Statistics (Statistisches Bundesamt, 2023).

10

Supplementary Table 2: Order of five revenue recycling schemes in the voting phase.

Task

State Budget

Redistribute All

Climate Premium

Redistribute Poor

Climate Projects

1
2
3
4
5

216
225
220
220
219

224
218
220
218
220

220
221
222
221
216

220
220
218
218
224

220
216
220
223
221

11

Supplementary Table 3: Policy support by demographic groups.

𝑁

State Climate
Budget Project

Redistribute
Poor

Redistribute
All

ClimatePremium

Birth year
19831963-1982
-1962

384
384
332

0.474
0.427
0.524

0.648
0.565
0.672

0.607
0.594
0.690

0.721
0.638
0.708

0.758
0.698
0.738

GenderFemale
Male

553
545

0.477
0.468

0.653
0.600

0.656
0.596

0.689
0.686

0.740
0.721

Education level
1
2
3
4

329
336
198
237

0.480
0.414
0.485
0.536

0.623
0.607
0.667
0.624

0.669
0.631
0.611
0.578

0.672
0.702
0.692
0.688

0.720
0.741
0.747
0.717

Income below e2,100
No
Yes

536
564

0.470
0.475

0.646
0.608

0.545
0.706

0.688
0.688

0.733
0.729

Party
CDU/CSUSPDDie Grünen
FDP
Die Linke
AfD

288
253
165
111
100
183

0.455
0.577
0.667
0.333
0.440
0.284

0.618
0.684
0.848
0.495
0.690
0.404

0.597
0.696
0.812
0.432
0.650
0.519

0.649
0.743
0.830
0.631
0.690
0.579

0.729
0.814
0.885
0.586
0.690
0.590

Political orientation
Conservative
NeutralLiberal

182
531
387

0.335
0.469
0.543

0.462
0.629
0.700

0.527
0.621
0.682

0.582
0.693
0.731

0.588
0.744
0.780

Climate concern
Low
High

234
866

0.269
0.528

0.372
0.695

0.449
0.676

0.504
0.738

0.513
0.790

Big city
No
Yes
N/A

421
654
25

0.470
0.472
0.520

0.610
0.639
0.560

0.653
0.612
0.600

0.701
0.683
0.600

0.751
0.717
0.760

Former East Germany
No
Yes

933
167

0.473
0.473

0.628
0.617

0.628
0.623

0.685
0.707

0.734
0.713

Notes: Education level: 1 (No secondary school certificate or Basic secondary school certificate), 2 (Intermediate
secondary school certificate or Other), 3 (Higher education entrance qualification), 4 (Bachelor’s/Master’s degree orDoctorate/Ph.D.). A city is classified as big city if it has more than 100,000 inhabitants, based on the data fromthe Federal Office of Statistics (Statistisches Bundesamt, 2023).

12

Supplementary Table 4: Voting decisions and the effect of demographic characteristics.
(1)
State Budget
Climate Projects
Redistribute Poor
Redistribute All
Climate Premium

(2)

(3)

(4)

0.154∗∗∗(0.016)
0.155∗∗∗(0.016)0.215∗∗∗(0.016)
0.258∗∗∗(0.016)−0.053∗∗(0.027)0.030(0.028)0.026(0.022)−0.004(0.029)0.019(0.035)0.015(0.036)0.024(0.024)0.154∗∗∗(0.016)
0.155∗∗∗(0.016)0.215∗∗∗(0.016)
0.258∗∗∗(0.016)−0.047∗(0.025)0.012(0.027)0.011(0.021)
0.006(0.028)0.010(0.033)−0.019(0.033)0.039∗(0.022)
0.094∗∗∗(0.030)0.120∗∗∗(0.032)0.114∗∗∗(0.021)0.227∗∗∗(0.027)−0.003(0.031)−0.003(0.008)0.454∗∗∗(0.038)0.011(0.029)−0.003(0.007)0.141∗∗∗(0.045)0.154∗∗∗(0.016)
0.155∗∗∗(0.016)0.215∗∗∗(0.016)
0.258∗∗∗(0.016)−0.048∗(0.025)0.007(0.027)0.011(0.021)
0.003(0.028)0.004(0.033)−0.034(0.034)0.048∗∗(0.022)0.082∗∗∗(0.030)0.095∗∗∗(0.032)0.112∗∗∗(0.021)0.197∗∗∗(0.028)0.029∗∗∗(0.005)−0.009∗∗(0.005)0.012(0.029)−0.002(0.007)0.038(0.054)

5,500
0.040

5,500
0.109

5,500
0.124

0.473∗∗∗(0.015)0.626∗∗∗(0.015)0.627∗∗∗(0.015)0.688∗∗∗(0.014)0.731∗∗∗(0.013)Birth year: 1963-1982
Birth year: -1962
FemaleEducation level: 2
Education level: 3
Education level: 4
Income below e 2,100
Pol. orientation: Neutral
Pol. orientation: Liberal
Trust in government: HighClimate concern: HighTime preferences
Risk preferences
Former East Germany
Big city
Constant
Observations
𝑅2

5,500
0.641

Notes: Linear probability model. The dependent variable is a dummy indicating support for the revenue recycling scheme. Model (1) does not include the constant. State Budget – Climate Premium are dummy variables
corresponding to each condition. List of control variables: age bracket (baseline: born after 1983), gender (baseline: male), education, income (baseline: above e 2,100), political orientation (baseline: conservative), trust in
government (baseline: low), climate concern (baseline: low), time/risk preferences (11 levels), former East Germany, and big city. Standard errors clustered at the individual level are reported in parentheses. ∗ : 𝑝 < 0.1; ∗∗ :𝑝 < 0.05; ∗∗∗ : 𝑝 < 0.01.

13

Supplementary Table 5: Demographic characteristics (expert survey).

PremiumAlle 1.40e 1.70

Age
18-29
30-39
40-49
50-59
60-69
70+

85 0.230
160 0.434
72 0.195
37 0.100
12 0.033
3
0.008

0.156
0.475
0.223
0.101
0.034
0.011

0.300
0.395
0.168
0.100
0.032
0.005

𝜒 2 (5) = 11.45
𝑝 = 0.043

GenderFemale
Male

116
250

0.317
0.683

0.337
0.663

0.298
0.702

𝜒 2 (1) = 0.48
𝑝 = 0.488

Position
Graduate Student
Postdoc, Assistant Professor
Associate Professor
Full Professor
Non-academic Researcher
Other

148
95
21
86
8
11

0.401
0.257
0.057
0.233
0.022
0.030

0.346
0.313
0.056
0.235
0.022
0.028

0.453
0.205
0.058
0.232
0.021
0.032

𝜒 2 (5) = 6.8
𝑝 = 0.236

𝑁

14

C

Instructions and the Interface

C.1

Main ExperimentConsent
Please read the following instructions carefully.

VoluntarinessYour participation in the experiment is voluntary. You can revoke your participation at any
time. If you end the experiment prematurely by closing the browser window, the data you
entered will be deleted. Please note, however, that you will not receive any payment.
Procedure
The experiment will take approximately 25 minutes.
During the course of the experiment, you will have to make some decisions. Each of thesedecision situations will be described in detail beforehand.
You must perform the experiment on a computer, laptop, or cell phone without interruption.
During the whole experiment, we ask you not to communicate with other people, not to startother programs on the computer, and not to use your cell phone for other purposes.
Please note that there are attention checks built into the experiment. If you do not answer
them correctly, you will be excluded from the experiment prematurely.
Confidentiality
All data collected will be analyzed anonymously. Your name will not be linked to any decisions
made in this experiment.
Payouts
For completed participation in this experiment, you will receive a monetary payout consistingof a fixed and variable amount.
Please note that you will not know your payout amount immediately at the end of the experiment. You will be informed about your payout amount separately in the coming days.

15

Declaration of consent
By clicking “I agree” below, you confirm that you are at least 18 years old, have readthe consent form, and agree to participate in this experiment under the rules and regulations listed.
[Consent] Do you agree to participate in this experiment?
□ I agree□ I do not agree

16

[1]
[0]

Questionnaire
Please first complete the following questionnaire. All answers will be completely anonymisedand cannot be associated with you after the experiment has been completed.
[Q.0.1] What is your year of birth? [Text box]
[Q.0.2] What is your gender?
□ Female□ Male□ Diverse

[1]
[2]
[3]

[Q.0.3] What is your highest educational qualification?
□ No secondary school certificate□ Basic secondary school certificate□ Intermediate secondary school certificate□ (Specialized) Higher education entrance qualification□ Bachelor’s/Master’s degree□ Doctorate/Ph.D.
□ Other: [Text box]

[1]
[2]
[3]
[4]
[5]
[6]
[7]

[Q.0.4] What is your occupation? [Text box]
[Q.0.5] We are now checking your attention. Please answer “Fully agree”.
□ Do not agree at all□ Strongly disagree□ Neither disagree nor agree□ Somewhat agree□ Fully agree

[1]
[2]
[3]
[4]
[5]

[Q.0.6] What is your monthly disposable income, i.e. the amount in euros that you can disposeof each month, after deduction of taxes and social security contributions, to finance all yourexpenses? [Text box]
[Q.0.7] What kind of device are you using to participate in this study?
□ Laptop or desktop computer□ Tablet□ Mobile phone

[1]
[2]
[3]

17

Welcome[1/5]This is a study by researchers at Ludwig Maximilian University of Munich.

[2/5]
The study takes approximately 25 minutes.
You will receive a payout for completed participation in this study.
[3/5]
Please read the instructions carefully.
We will ask you questions that will test your understanding and attention. If you
answer them incorrectly, unfortunately, you will not be able to participate in the
study and will not receive any bonus payment.
You can only proceed if you answer all the questions in the quiz correctly. If you
want to return to the instructions, please click on the ← button.

[4/5]
The experiment consists of 4 parts.
• In Part 1 and Part 2, you make purchase decisions. One of the two parts is selected anddetermines your bonus payout.
• In Part 3, you make several decisions that affect which of the top two parts is selected.
• In Part 4, you fill out a questionnaire.

18

[5/5]The Ethics Committee of LMU Munich has approved this study. You can contact
the Ethics Committee via ethics-committee@econ.lmu.de.
In order to obtain approval, we have pledged not to provide misleading or untrue
information.
Everything you read in the instructions is TRUE.

Quiz[CQ.0] According to the ethics protocol under which we are conducting this study, all information you read must be truthful and not misleading.
□ True□ False

[1]
[2]

19

Part 1
[1/8]
In Part 1, you can buy two “virtual” products:
Product ORANGE and Product BLUE.

[2/8]
When you buy a product, you will receive the following payout.
• The value of Product ORANGE is 7 euros.

• The value of Product BLUE is 5 euros.

• Each product costs 3 euros.

20[3/8]
If you buy Product ORANGE and Product BLUE, you will receive a total of 6 euros.

If you buy only Product ORANGE, you will receive 4 euros.

You can not buy Product BLUE alone.
If you do not buy any product, you will receive 0 euros.

[4/8]
When you buy products, you emit CO2 .
Emissions are equal to 60kg of CO2 for each product you purchase.

60kg is approximately equal to the amount of CO2 produced by a 300 km car trip.
Scientists agree that CO2 emissions are the most important cause of climate change.

21[5/8]
If you buy both Product ORANGE and Product BLUE, you will receive a total of 6 euros
and you emit 120kg of CO2 .

If you buy only Product ORANGE, you will receive 4 euros and you emit 60kg of CO2 .

If you do not buy either product, you will receive 0 euros and you will not emit any CO2 .

[6/8]
Your purchase decision has a real impact on CO2 emissions.
Here we explain why this is so. There is an organisation called Carbonfund.org
that carries out projects that permanently reduce CO2 in the earth’s atmosphere.
For a fixed amount, Carbonfund.org reduces the CO2 content of the atmosphereby one ton.
The experimental laboratory of the LMU Munich (MELESSA) has pledged, via
Carbonfund.org, to remove 120kg of CO2 from the atmosphere for each participant in this experiment. However, this amount decreases by 60kg with eachproduct purchased. So, if you buy both products, 120kg less CO2 will be neutralised, i.e. there will be permanently 120kg more CO2 in the atmosphere than
if you do not buy any product.

[7/8]
You will receive a link to the receipt proving our purchase of CO2 certificates via Carbonfund.org approximately 2 weeks after the end of the study.
So you can be sure that the transfer to Carbonfund.org is really done.

22[8/8]
In summary, you will select one of the following three options in this part.
• Option 1: You buy both Product ORANGE and Product BLUE

• Option 2: You buy only Product ORANGE• Option 3: You do not buy a product

Before proceeding, you must complete a quiz.
Quiz[CQ.1.1] 1. What happens when you buy both products?
□ You receive a total of 6 euros and emit 120kg of CO2 .
□ You receive a total of 4 euros and emit 60kg of CO2 .
□ You receive 0 euros and emit no CO2 .

[1]
[2]
[3]

[CQ.1.2] 2. What happens if you buy only Product ORANGE?
□ You receive a total of 6 euros and emit 120kg of CO2 .
□ You receive a total of 4 euros and emit 60kg of CO2 .
□ You receive 0 euros and emit no CO2 .

[1]
[2]
[3]

[CQ.1.3] 3. What happens if you do not buy a product?
□ You receive a total of 6 euros and emit 120kg of CO2 .
□ You receive a total of 4 euros and emit 60kg of CO2 .
□ You receive 0 euros and emit no CO2 .

[1]
[2]
[3]

[CQ.1.4] 4. Your decisions affect the level of CO2 in the atmosphere.
□ True□ False

[1]
[2]

23

Your decision for Part 1
Please select an option.
□ Option 1: You buy both Product ORANGE and Product BLUE

□ Option 2: You buy only Product ORANGE□ Option 3: You do not buy a product24Part 2
[1/4]
In Part 2, you can again buy two products, Product ORANGE and Product BLUE. Theirvalues are the same as in Part 1, and you emit 60kg of CO2 for each product you buy.
• Product ORANGE has a value of 7 euros, and emits 60kg CO2.

• Product BLUE has a value of 5 euros, and emits 60kg CO2.

[2/4]
In Part 2, the price for each product is 6 euros.

[3/4]
If you buy Product ORANGE and Product BLUE, you will receive a total of 0 euros.

If you buy only Product ORANGE, you will receive 1 euro.

You can not buy Product BLUE alone.
If you do not buy any product, you will receive 0 euros.
25

[4/4]
In summary, you will select one of the following three options in this part.
• Option 1: You buy both Product ORANGE and Product BLUE

• Option 2: You buy only Product ORANGE• Option 3: You do not buy a product

Before proceeding, you must complete a quiz.
Quiz[CQ.2] The price in Part 2 is ...
□ lower than in Part 1.
□ the same as in Part 1.
□ higher than in Part 1.

[1]
[2]
[3]

26

Your decision for Part 2
Please select an option.
□ Option 1: You buy both Product ORANGE and Product BLUE

□ Option 2: You buy only Product ORANGE□ Option 3: You do not buy a product[Following message pops up if a participant chose Option 1.]
Are you sure you want to buy both products?
Please note: The additional purchase of Product BLUE will reduce your payout
and increase CO2 emissions.

27Part 3
[1/7]
In this experiment, you are part of a group of 50 consumers. You will remain part of thisgroup for the entire study.
Each member of the group has or will answer exactly the same questions as you.

[2/7]
Your group members are drawn from a representative sample of the German populationin terms of gender, age, region, education, and income.
This means, for example, that since 51% of the German population is female, a randomly
selected member of your group has a 51% probability of being female.
[3/7]
You now take part in 5 votes. At the end of the study, the computer randomly draws a number
between 1 and 5. This number decides which of the 5 votes is payout-relevant.
One of the 50 group members is randomly selected and her or his vote alone decides theoutcome of the payout-relevant vote.

Important: This group member could be you! Therefore, in all votes you should vote forthe option you think is better.
Before proceeding, you will have to complete a quiz.

28

Quiz
[CQ.3.1] 1. Which statement is true about your group members?
□ Your group members come from a representative sample of the German population interms of gender, age, region, education, and income.
[1]□ Your group members are not representative of the German population in terms of gender, age, region, education, and income.
[2][CQ.3.2] 2. Which of the following statements is true about your choices in this part?
□ It is certain that my decisions in this part will determine the outcome of the payoutrelevant vote.
[1]□ There is a small chance that my decisions in this part will determine the outcome of thepayout-relevant vote.
[2]□ There is no chance that my decisions in this part will determine the outcome of thepayout-relevant vote.
[3]
[4/7]
In Part 1, the price for each product was 3 euros. In Part 2, the price for each product was 6
euros.
The price in Part 2 was higher than in Part 1 because in Part 2, in addition to the product priceof 3 euros, a CO2 price of 3 euros had to be paid per product (this corresponds to a CO2 priceof 50 euros per ton of CO2 ).

The CO2 price was introduced to reduce the total amount of emissions.
[5/7]
The money generated by the CO2 price in this group goes into a common pot.

29

[This screen is for “State budget” condition][6/7]

The money in the common pot goes to the German state budget.
All taxes paid to the federal government go into the German state budget.

[6/7][This screen is for “Redistribute all” condition]

The money in the common pot will be divided equally among all 50 groupmembers.
You will receive this payment approximately 2 weeks after the end of the study.

[6/7][This screen is for “Climate premium” condition]

To compensate for the CO2 price, each group member receives an additional Climate Premium of 1.4/1.7 euros.
You will receive this payment immediately after completing the survey.
The payment is fixed and independent of the amount of money in the commonpot (but the pot helps with funding).

30

[6/7][This screen is for “Redistribute poor” condition]

The money in the common pot is divided equally among group members
who reported having a monthly disposable income of less than 2,100 euros.
In a previous study, 50% of participants had a monthly disposable income of lessthan 2,100 euros.
You reported a monthly disposable income of [≤ 2100]/[> 2100] euros, so you
will/will not receive a portion of the money.
You will receive this payment about 2 weeks after the end of the study.

[6/7][This screen is for “Climate project” condition]

The money in the common pot is transferred to an organisation supported by the National Climate Protection Initiative, through which theGerman government has been funding climate protection projects in Germany since 2008.
The National Climate Protection Initiative covers “a broad spectrum of climate
protection activities: From the development of long-term strategies to concrete
assistance and investment support measures.”

31

Quiz
[CQ.3.3] What happens to the money in the common pot?
□ It remains with the researchers.
[1]□ [State budget] It goes to the German state budget.
[2]□ [Redistribute all] It is divided equally among all group members.
[2]□ [Climate premium] Each participant receives a fixed additional payout of 1.4/1.7 euros
as a climate premium.
[2]□ [Redistribute poor] It will be divided equally among the group members who have declared having a monthly disposable income of less than 2,100 euros.
[2]□ [Climate project] It is transferred to an organisation supported by the National Climate
Protection Initiative.
[2]
[7/7]
You can now vote on which decisions in the study are payout-relevant.
You can vote for one of the following two options.
• The decisions without a CO2 price are payout-relevant (Part 1).
• The decisions with a CO2 price are payout-relevant (Part 2).

Decisions in Part 1: Without CO2 priceDecisions in Part 2: With CO2 price

The money in the common pot goes to
the German state budget.

[This illustration is for “State budget” condition]

32

Your decision for Vote 1
Please select an option.
I vote against the introduction of CO2
pricing (Part 1).

I vote for the introduction of CO2 pricing (Part 2).

Please explain in a few complete sentences why you decide against or in favour of the introduction of CO2 pricing. [Text box]

Part 1

Part 2The money in the common pot goes to
the German state budget.

[This illustration is for “State budget” condition]

33

Votes 2 to 5
For each of the following scenarios, you vote again on the introduction of a CO2 price.
As before, the money generated by the CO2 price in this group goes into a common pot inall subsequent scenarios.

The scenarios differ from each other because the money in the common pot is used differently.
Remember: There is a small chance that your vote will decide which part of the experimentis implemented for you and your group.

[Similar sets of instructions, quiz, and decision screen follow.]34

Part 4This is the last part of the study. Please answer the questions on the next pages.

Questionnaire [1/5][Q.4.1.1] 1.1. The following scenarios differ in how the revenues from CO2 pricing are distributed. Please now rank the five possible scenarios in order of how desirable you consider
them to be. Please place your preferred distribution on the 1 and your least preferred on the
5. [Order randomised]• The money in the common pot is divided equally among group members who havedeclared having a monthly disposable income of less than 2,100 euros.
• To compensate for the CO2 price, each group member will receive an additional paymentof 1.4/1.7 euros.
• The money in the pot goes to the German state budget.
• The money in the common pot will be transferred to an organisation supported by the
National Climate Protection Initiative, through which the German government has beenfunding climate protection projects in Germany since 2008.
• The money in the common pot is divided equally among all group members.
[Q.4.1.2] 1.2. In Part 3, you voted several times against or in favour of a CO2 price of 3 euros
for each product purchased. Please refer to Vote 1 in Part 3, in which the money generated
by the CO2 price ... [description of the redistribution scheme]. Imagine if the CO2 price had
been different. Would you agree to CO2 pricing for the following six scenarios?

CO2 price of 0.5 euros
CO2 price of 1.5 euros
CO2 price of 2.5 euros
CO2 price of 3.5 euros
CO2 price of 4.5 euros
CO2 price of 5.5 euros

Yes

No

□
□
□
□
□
□

□
□
□
□
□
□

[Q.4.1.3] 1.3. Please indicate how strongly you agree with the following statement: Insteadof a tax, the purchase of product BLUE should be banned altogether.
□ Strongly disagree□ Disagree□ Neutral□ Agree□ Strongly agree

[1]
[2]
[3]
[4]
[5]
35

Questionnaire [2/5]
The following seven questions are about your expectations regarding the behaviour of theother group members. You will be rewarded for the accuracy of your answers. For this, oneof the following seven questions will be randomly selected and you will receive an additional
10.00 euros if you have given the correct answer.
[Q.4.2.1] 2.1. Please refer to Part 1, where there was no CO2 pricing and the price for eachproduct purchased was therefore 3 euros. How many of the other 49 group members do you
think chose each of the three options?
Move the sliders below to express your guess. Note that the sum of the three answers must
add up to 49.
Buy both Product ORANGE
and Product BLUE

0

10

20

29

39

49

Buy Product ORANGE only
Do not buy a productTotal:

0[Q.4.2.2] 2.2. Please refer to Part 2, where there was a CO2 price of 3 euros for each productpurchased and the price for each purchased product was therefore 6 euros. How many of theother 49 group members do you think chose each of the three options?
Move the sliders below to express your guess. Note that the sum of the three answers must
add up to 49.
Buy both Product ORANGE
and Product BLUE

0

10

20

29

39

49

Buy Product ORANGE only
Do not buy a productTotal:

036

[Q.4.2.3] 2.3. In Part 3, how many of the other 49 group members voted in favour of introducing a CO2 price in each case? [Order randomised]0
The money in the pot goes to the German state budget.
As compensation for the CO2 price, each group member
receives an additional payment of e 1.40/1.70.
The money in the common pot is transferred to an organization supported by
the National Climate Protection Initiative, with which the German governmenthas been funding climate protection projects in Germany since 2008.
The money in the common pot is divided equally among all group members.
The money in the common pot is divided equally among group members
who have reported having a monthly disposable income of less than e 2,100.

37

10

20

29

39

49

Questionnaire [3/5]
We would like to know even more about you now.
[Q.4.3.1] 3.1. Where would you rank yourself if 1 stands for “The government should stayout of the economy and trust the market” and 5 stands for “The government should control
the economy”?
[Q.4.3.2] 3.2. Where would you rank yourself if 1 stands for “The state should stay out of theredistribution of income and wealth” and 5 stands for “The state should redistribute income
and wealth”?
[Q.4.3.3] 3.3. Where would you classify yourself if 1 stands for “socially conservative” and 5
for “socially liberal”?
[Q.4.3.4] 3.4. Which of the following parties is closest to your political views? [Order randomised]□ AfD□ Bündnis 90/Die Grünen□ CDU/CSU□ Die Linke
□ FDP
□ SPD
[Q.4.3.5] 3.5. Please indicate how strongly you agree with the following statements. [1:Strongly disagree; 3: Neutral; 5: Strongly agree]• If the government levies a tax to solve a problem, the revenue from that tax should be
used to solve the same problem. For example, the revenue from tobacco taxes should
be used to fund the health care system.
• The impact of new policies on people’s finances should be easy to understand. The
government should introduce simple measures, even if more complicated ones are more
effective.
• If the government wants people to change their behaviour, it should compensate themfor the cost of change.
• We now check your attention. Please answer “Disagree”.
• I have confidence in the German government to use taxpayers’ money wisely.
[Q.4.3.6] 3.6. Please tell us in general terms how much you are willing or unwilling to takerisks. Please use a scale from 0 to 10, where 0 means ‘not at all willing to take risks’ and 10
means ‘very willing to take risks’. You can also use any number between 0 and 10 to indicate
where you see yourself on the scale by using (the numbers) 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
38

[Q.4.3.7] 3.7. How much would you be willing to give up something that benefits you today
in order to benefit more in the future? Again, please use a scale from 0 to 10. 0 means ‘notat all willing to do this’ and 10 means ‘very willing to do this’. You can also use any number
between 0 and 10 to indicate where you see yourself on the scale by using (the numbers) 0, 1,
2, 3, 4, 5, 6, 7, 8, 9, or 10.

39

Questionnaire [4/5][Q.4.4.1] 4.1. Please indicate how strongly you agree with the following statements. [1:Strongly disagree; 3: Neutral; 5: Strongly agree]• I am convinced that climate change exists.
• I am convinced that climate change is mainly caused by humans.
• I am concerned about climate change.
• The emission of CO2 should be regulated.
[Q.4.4.2] 4.2. Climate change is a significant problem. [1: Strongly disagree; 3: Neutral; 5:Strongly agree][Q.4.4.3] 4.3. How likely is it that humanity will stop climate change by the end of the century? [1: Very unlikely; 4: Very likely][Q.4.4.4] 4.4. To what extent do you think climate change is already affecting or will negatively affect your life? [1: Not at all; 2: A little; 3: Moderately; 4: Quite a lot; 5: Very much][Q.4.4.5] 4.5. Germany should bear a large part of the cost of combating climate change. [1:Strongly disagree; 3: Neutral; 5: Strongly agree][Q.4.4.6] 4.6. Germany should provide substantial financial assistance to the countries mostaffected by the consequences of climate change. [1: Strongly disagree; 3: Neutral; 5: Strongly
agree][Q.4.4.7] 4.7. How many countries in the world have produced more CO2 emissions in theircountries have polluted more than Germany.
entire history than Germany?
[Q.4.4.8] 4.8. How many countries in the world are more vulnerable to climate change than
Germany?
Countries are more vulnerable to climate change.
[Q.4.4.9] 4.9. You now have the choice between several options, which differ in an additional
payout for you and an additional CO2 compensation by Carbonfund.org. The option you
choose will be implemented by us. Please indicate which of the following options you prefer:□ 0.50 euros for you and 0kg additional CO2 compensation□ 0.40 euros for you and 8kg additional CO2 compensation□ 0.30 euros for you and 14kg additional CO2 compensation□ 0.20 euros for you and 18kg additional CO2 compensation□ 0.10 euros for you and 20kg additional CO2 compensation□ 0.00 euros for you and 21kg additional CO2 compensation

40

[1]
[2]
[3]
[4]
[5]
[6]

Questionnaire [5/5][Q.4.5.1] 5.1. Do you trust those responsible for this study that they will indeed buy CO2
certificates as described in the instructions?
□ Yes
□ No

[1]
[2]

[Q.4.5.2] 5.2. Do you have feedback on this survey? [Text box]

41

C.2

Expert Survey

Welcome to this study!
VoluntarinessYour participation in the experiment is voluntary. You can revoke your participation at any
time.
Procedure
The study will take approximately 10 minutes.
Confidentiality
All data collected will be analyzed anonymously.
Payouts
You may receive a monetary payment for completing your participation in this study.
Declaration of consent
By clicking “I agree” below, you confirm that you are at least 18 years old, have readthe consent form, and agree to participate in this experiment under the rules and regulations listed.
[Consent] Do you agree to participate in this experiment?
□ I agree□ I do not agree

42

[1]
[0]

Welcome[1/2]
Thank you for your participation! In this study, we kindly request your assessment of thelevel of approval within the German population for various forms of CO2 pricing.
We collected this approval through an online experiment in June 2023 with 1,100 participants.
The participants were recruited through the online platform Bilendi and are representative of
the adult German population in terms of• age,• gender,• region,• income, and• education.
Both the experiment and this study were preregistered.
[2/2]
You will now be taken quickly through the original experiment. This experiment consisted of
4 parts.
In Parts 1 to 3, you will make the same decisions as the experiment participants. Unlike theexperiment, your decisions in Parts 1 to 3 are hypothetical.
In Part 4, we will ask you for incentivised assessments of the decision-making behaviour ofthe experiment participants.

43

Part 1
[1/5]
In Part 1, you can buy two “virtual” products:
Product ORANGE and Product BLUE.

[2/5]
When you buy a product, you will receive the following payout.
• The value of Product ORANGE is 7 euros.

• The value of Product BLUE is 5 euros.

• Each product costs 3 euros.

44

[3/5]
If you buy Product ORANGE and Product BLUE, you will receive a total of 6 euros.

If you buy only Product ORANGE, you will receive 4 euros.

You can not buy Product BLUE alone.
If you do not buy any product, you will receive 0 euros.

[4/5]
When you buy products, you emit CO2 .
Emissions are equal to 60kg of CO2 for each product you purchase.

60kg is approximately equal to the amount of CO2 produced by a 300 km car trip.
Scientists agree that CO2 emissions are the most important cause of climate change.

45

[5/5]Your purchase decision has a real impact on CO2 emissions.
Here we explain why this is so. There is an organisation called Carbonfund.org
that carries out projects that permanently reduce CO2 in the earth’s atmosphere.
For a fixed amount, Carbonfund.org reduces the CO2 content of the atmosphereby one ton.
The experimental laboratory of the LMU Munich (MELESSA) has pledged, via
Carbonfund.org, to remove 120kg of CO2 from the atmosphere for each participant in this experiment. However, this amount decreases by 60kg with eachproduct purchased. So, if you buy both products, 120kg less CO2 will be neutralised, i.e. there will be permanently 120kg more CO2 in the atmosphere than
if you do not buy any product.

46

Your decision for Part 1
Please select an option.
□ Option 1: You buy both Product ORANGE and Product BLUE

□ Option 2: You buy only Product ORANGE□ Option 3: You do not buy a product47

Part 2
[1/3]
In Part 2, you can again buy two products, Product ORANGE and Product BLUE. Theirvalues are the same as in Part 1, and you emit 60kg of CO2 for each product you buy.
• Product ORANGE has a value of 7 euros, and emits 60kg CO2.

• Product BLUE has a value of 5 euros, and emits 60kg CO2.

[2/3]
In Part 2, the price for each product is 6 euros.

[3/3]
If you buy Product ORANGE and Product BLUE, you will receive a total of 0 euros.

If you buy only Product ORANGE, you will receive 1 euro.

You can not buy Product BLUE alone.
If you do not buy any product, you will receive 0 euros.
48

Your decision for Part 2
Please select an option.
□ Option 1: You buy both Product ORANGE and Product BLUE

□ Option 2: You buy only Product ORANGE□ Option 3: You do not buy a product[Following message pops up if a participant chose Option 1.]
Are you sure you want to buy both products?
Please note: The additional purchase of Product BLUE will reduce your payout
and increase CO2 emissions.

49Part 3
[1/4]
In this experiment, you are part of a group of 50 consumers. You will remain part of thisgroup for the entire study.
Each member of the group has or will answer exactly the same questions as you.
You now take part in 5 votes. At the end of the study, the computer randomly draws a number
between 1 and 5. This number decides which of the 5 votes is payout-relevant.
One of the 50 group members is randomly selected and her or his vote alone decides theoutcome of the payout-relevant vote.

[2/4]
In Part 1, the price for each product was 3 euros. In Part 2, the price for each product was 6
euros.
The price in Part 2 was higher than in Part 1 because in Part 2, in addition to the product priceof 3 euros, a CO2 price of 3 euros had to be paid per product (this corresponds to a CO2 priceof 50 euros per ton of CO2 ).

The CO2 price was introduced to reduce the total amount of emissions.
[3/4]
For the following five scenarios, you will vote on the introduction of CO2 pricing.
You can vote for one of the following two options in each case.
• The decisions without a CO2 price are payout-relevant (Part 1).
• The decisions with a CO2 price are payout-relevant (Part 2).

50

[4/4]The money generated by the CO2 price in this group goes into a common pot.

The scenarios differ in how the money in the common pot is used.

51

Your decision for Vote 1
Please select an option.
I vote against the introduction of CO2
pricing (Part 1).

I vote for the introduction of CO2 pricing (Part 2).

Part 1

Part 2The money in the common pot goes to
the German state budget.

[This illustration is for “State budget” condition. Decision pages for Votes 2 to 5 follow.][Q.3.ranking] The following scenarios differ in how the revenues from CO2 pricing are distributed. Please now rank the five possible scenarios in order of how desirable you consider
them to be. Please place your preferred distribution on the 1 and your least preferred on the
5. [Order randomised]• The money in the common pot is divided equally among group members who havedeclared having a monthly disposable income of less than 2,100 euros.
• To compensate for the CO2 price, each group member will receive an additional paymentof 1.4/1.7 euros.
• The money in the pot goes to the German state budget.
• The money in the common pot will be transferred to an organisation supported by the
National Climate Protection Initiative, through which the German government has beenfunding climate protection projects in Germany since 2008.
• The money in the common pot is divided equally among all group members.

52

Part 4
[1/2]
This is the last part of the study.
In the following seven questions, we will ask about your expectations regarding the
behaviour of the 1,100 experiment participants.
You will be compensated for the accuracy of your answers. One of the following seven questions will be randomly selected, and you will receive e 40 if your answer deviates by a maximum of 2 percentage points from the correct answer.
[Q.4.1.1] 1.1. Please refer to Part 1, where there was no CO2 pricing and the price for eachproduct purchased was therefore 3 euros. What percentage of the experiment participantschose each of the three options?
Move the sliders below to express your guess. Note that the sum of the three answers must
add up to 100.
Buy both Product ORANGE
and Product BLUE

0

10

20

30

40

50

60

70

80

90 100

Buy Product ORANGE only
Do not buy productTotal:

0[Q.4.1.2] 1.2. Please refer to Part 2, where there was a CO2 price of 3 euros for each productpurchased and the price for each purchased product was therefore 6 euros. What percentageof the experiment participants chose each of the three options?
Move the sliders below to express your guess. Note that the sum of the three answers must
add up to 100.
Buy both Product ORANGE
and Product BLUE

0

10

20

30

40

50

60

70

80

90 100

Buy Product ORANGE only
Do not buy productTotal:

053

[Q.4.1.3] 1.3. What percentage of the experiment participants chose to introduce CO2 pricing
in Part 3?
0 10 20 30 40 50 60 70 80 90 100
The money in the pot goes to the German state budget.
As compensation for the CO2 price, each group member
receives an additional payment of e 1.40/1.70.
The money in the common pot is transferred to an organisation supported by
the National Climate Protection Initiative, with which the German governmenthas been funding climate protection projects in Germany since 2008.
The money in the common pot is divided equally among all group members.
The money in the common pot is divided equally among group members
who have reported having a monthly disposable income of less than e 2,100.

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[2/2]
Thank you for your participation. This is the final section of the survey. We would appreciate
it if you could share some information about yourself. This information will only be used to
distinguish patterns in the responses of different expert types.
[Q.4.2.1] 2.1. How old are you?
□ 18-29 years old□ 30-39 years old□ 40-49 years old□ 50-59 years old□ 60-69 years old□ 70+ years old

[1]
[2]
[3]
[4]
[5]
[6]

[Q.4.2.2] 2.2. What is your gender?
□ Female□ Male□ Diverse

[1]
[2]
[3]

[Q.4.2.3] 2.3. What position do you hold?
□ Graduate Student (Master, PhD)
□ Junior Faculty (Post-Doc, Assistant Professor)□ Associate Professor□ Full Professor□ Non-academic Researcher□ Other: [Text box]

[1]
[2]
[3]
[4]
[5]
[7]

[Q.4.2.4] 2.4. If you have any comments, please enter them below. We would like to hear
your feedback. [Text box]
Through the following link, you can provide your email address. This will allow us to contact
you if you have won e 40 in the previous assessment questions. Please enter the following
code: XXXXXXXX
Link: https://melessa.limequery.com/XXXXXXXX

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References
Statistisches Bundesamt, “Städte (Alle Gemeinden mit Stadtrecht) nach Fläche,Bevölkerung und Bevölkerungsdichte am 31.12.2022,” 2023.
Statistisches Bundesamt.
https://www.destatis.de/DE/Themen/Laender-Regionen/Regionales/
Gemeindeverzeichnis/Administrativ/05-staedte.html.

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