Wealth inequality perception and wealth tax preferences in Spain

Last registered on September 15, 2023


Trial Information

General Information

Wealth inequality perception and wealth tax preferences in Spain
Initial registration date
September 11, 2023

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
September 15, 2023, 8:54 AM EDT

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


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Primary Investigator

Research Scholar Universidad Complutense de Madrid / Associate Fellow INET Oxford

Other Primary Investigator(s)

PI Affiliation
Universidad Complutense de Madrid

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
The trial consists on an online survey in which Spanish respondents from a representative sample are asked questions about their perception of wealth inequality in Spain. Then, some of them are randomly provided with some factual information about the current estimated values of wealth inequality in Spain. After that, both control and treated group respond to questions about their preferences for wealth taxation and about different possible schemes for such wealth taxation.

One objective of the study is to measure the possible bias or discrepancy in people's perception of wealth inequality; then, a second question we are interested in is whether people who are informed (treated group) about the current actual levels of wealth inequality correct that bias; finally, the main goal of the study will be to measure how that perception correction affects preferences for wealth taxation in general and/or for different types of wealth taxation schemes.

This trial is a sibling trial of one previously submitted and approved by AEA RCT Registry for the United Kindgom (https://doi.org/10.1257/rct.10698-1.0), in which data collection is already completed.

Results of both trials will be analysed independently and results for both trials compared and put in the context of their respective country profiles, aiming to provide an overview of the commonalities and differences found between the two countries' population.
External Link(s)

Registration Citation

Palomino, Juan C. and Raquel Sebastian. 2023. "Wealth inequality perception and wealth tax preferences in Spain." AEA RCT Registry. September 15. https://doi.org/10.1257/rct.11777-1.0
Sponsors & Partners

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Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
For treated and untreated, we are aiming to see the effect on: Preference for having wealth taxation, preference for different exemption thresholds in such taxation, preference for different types of assets taxed, difference in the implicit tax rate revealed by the respondents
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Correction of possible perception biases about wealth inequality (treated group); different perception biases for different demographic groups
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experimental design will be applied in an online survey distributed to a representative sample, using simple quotas for four dimensions: age groups, gender, region (Spanish Autonomous Comunities), and interlocking quotas for gender and age.

First step:
All respondents are asked questions about their perception of wealth inequality in the Spain and about demographic characteristics (gender, marital status, etc.) and some economic circumstances (their broad own wealth assets, income). They will also answer to some questions about their perception of the government and of taxes in general prior to the treatment.

Second step:
Half of the respondents will be given information about wealth inequality in the Spain (treated group) while the other half will not see that information. [Given the relatively big sample, we expect treatment/non treatment to naturally distribute equally in all broad demographics groups through simple randomisation.]

Third step:
Check information acquisition/bias correction through a second set of questions about wealth inequality posed "post-treatment".

Fourth step:
Investigate differences in wealth taxation preferences between treated and untreated group.
This differences in preferences will be refer to: overall wealth taxation, taxation to different wealth assets, exemption thresholds for taxation, implicit tax rates for wealth taxation, different earmarking of wealth taxation revenue.

Fifth step:
This differences in the effect will be cross-analysed for different subgroups of the population based on socio-demographic differences and on pre-treatment differences in perceptions.

Sixth step:
The differences will be also compared to those of the United Kingdom, in which a sibling trial would be run on a project registered separately (https://doi.org/10.1257/rct.10698-1.0)
Experimental Design Details
Not available
Randomization Method
Randomization done by a computer when distributing the online survey.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
The treatment will be applied individually. So 3000 clusters = 3000 individuals.
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
1500 observations treated; 1500 observations untreated
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number