Field study of choice-matching for eliciting stated preferences

Last registered on January 06, 2021


Trial Information

General Information

Field study of choice-matching for eliciting stated preferences
Initial registration date
January 06, 2021

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
January 06, 2021, 9:59 AM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.



Primary Investigator

University of Warsaw

Other Primary Investigator(s)

PI Affiliation
University of Warsaw

Additional Trial Information

In development
Start date
End date
Secondary IDs
The study aims at testing empirically the theoretical approach of choice-matching proposed by Cvitanić et al. (2019, AER: Insights, 1(2), 179-192) for incentivizing truthful responding. We apply the proposed framework to the context of stated preferences. While the choice-matching approach is originally designed for incentivizing responses to a multiple choice question, we illustrate its possible application to an open-ended question. To that end, we conduct an online experiment, mirroring a standard stated preference survey as used for valuation of public goods. We implement two versions of the survey questionnaire: one employing the incentive-compatible choice-matching approach and another representing a common hypothetical setting. The two survey versions differ only with respect to necessary characteristics for implementing the choice-matching. In particular, both versions employ the same open-ended question for eliciting individual's willingness-to-pay values for a public good. The good is a policy project of installing solar panels in public spaces of the city of Warsaw in Poland (e.g., railway stations) so that these places could increase their green energy use. We inquire whether willingness-to-pay values are different when stated under the choice-matching approach than when expressed in standard conditions without any incentivization to truthful responding.
External Link(s)

Registration Citation

Krawczyk, Michał and Ewa Zawojska. 2021. "Field study of choice-matching for eliciting stated preferences." AEA RCT Registry. January 06.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The key outcome variable is willingness-to-pay statements in the open-ended preference elicitation question. The study will reveal whether preferences stated in an open-ended valuation question are statistically different or not between the theoretically incentive-compatible choice-matching approach and a standard, not incentive-compatible, hypothetical setting. While there could be many interpretations behind any of the two outcomes, we will try to control for the interpretations, using additional questions included at the end of the survey.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The economic experiment will be conducted online on a sample of about 200 respondents randomly invited to participate in the study from the panel of registered participants to economics experiments of the Laboratory of Experimental Economics at the Faculty of Economic Sciences of the University of Warsaw. The experiment will have a form of a short online survey (lasting about 20 minutes), and two versions of the questionnaire will be developed: one employing the choice-matching approach and the other one representing a common hypothetical setting without any incentives for truthful responding. Other than the differences required by the implementation of the choice-matching approach, the questionnaires will be identical.
Randomly selected participants from the panel will receive email invitations with a link to the survey. Specific time (about a week) will be allotted for the participants to complete the survey. Upon starting the survey, each participant will be randomly assigned to one of the two versions of the questionnaire. Participants will not be made aware of the two versions.
Experimental Design Details
After the screening questions verifying that a participant lives in Warsaw and pays taxes in the city, the major part of the survey will be displayed. It will consist of two parts.
In Part 1, participants will be asked how much money they want to donate for planting woods in Poland by Foundation “Las na Zawsze” having 1,000 Polish zloty (PLN) at their disposal. For three randomly selected participants, this decision will be binding--we will transfer the money amounts indicated by them to the foundation, while the remaining money of the assigned 1,000 PLN will be transferred to the participant in question.
In Part 2, the open-ended preference elicitation question will be shown. That is, participants will be asked how much money they would be willing to pay in a form of an increased tax for a period of five years for a city project of installing solar panels in public spaces of Warsaw to extend green energy use. In this part, participants of the choice-matching approach will be provided with an additional incentivization mechanism. These participants will be told that in addition to the earlier draw, three more individuals will be randomly selected, who will be assigned 1,000 PLN and part of this amount will be transferred to the foundation, while the remaining money will be transferred to them. Now (i.e., in the second draw), the amount for the foundation will be the average amount indicated in the question about donating for planting woods by those participants who stated in the willingness-to-pay question about solar panels a similar tax amount to the selected individual. This mechanism is a direct implementation of the choice-matching method.
Upon completion of the main part, follow-up questions will be asked to better understand the participants’ decisions. These questions will include measures of understanding the experiment instructions, indicators of pro-environmental behaviors, and socio-demographic characteristics, among others.
Randomization Method
Randomization is done by a computer for both randomized assignment of individuals to treatments (survey versions) and randomized selection of individuals for whom the decisions are binding
Randomization Unit
Randomization at the individual level
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
200 individuals
Sample size: planned number of observations
200 individuals
Sample size (or number of clusters) by treatment arms
100 individuals in the standard survey version and 100 individuals in the choice-matching approach
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Ethics Committee of the Faculty of Economic Sciences of the University of Warsaw
IRB Approval Date
IRB Approval Number


Post Trial Information

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

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Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials