Tax Consent and Tax Complexity

Last registered on August 25, 2025
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Pre-Trial

Trial Information

General Information

Title
Tax Consent and Tax Complexity
RCT ID
AEARCTR-0016413
Initial registration date
August 24, 2025

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
August 25, 2025, 8:51 AM EDT

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

Locations

Country
France
Region

Primary Investigator

Name
Emmanuelle TAUGOURDEAU
Affiliation
CREST, CNRS, IPParis
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Other Primary Investigator(s)

PI Name
Pierre Boyer
PI Affiliation
CREST, École polytechnique, Institut Polytechnique de Paris
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PI Name
Bertrand Garbinti
PI Affiliation
CREST, ENSAE, Institut Polytechnique de Paris
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Additional Trial Information

Status
In development
Start date
2025-09-07
End date
2025-09-30
Keywords
Behavior, Governance, Welfare
Additional Keywords
Taxes, Tax consent, Tax complexity, Survey, Political Economy
JEL code(s)
C93, D91, H21, H24
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Conventional wisdom suggests that most tax systems are overly complex and that simplification is broadly desirable (Blesse et al., 2019). But does this perception influence tax consent? To explore this question, we aim to evaluate the causal effect of individuals’ perceptions of tax system complexity on their willingness to comply with taxes. To that end, we employ informational treatments to test whether these perceptions shift when individuals are presented with objective data on the complexity of the French tax system. We then assess whether any resulting changes in perception influence both attitudes toward tax complexity and overall tax consent.
External Link(s)

Registration Citation

Citation
Boyer, Pierre, Bertrand Garbinti and Emmanuelle TAUGOURDEAU. 2025. "Tax Consent and Tax Complexity." AEA RCT Registry. August 25. https://doi.org/10.1257/rct.16413-1.0
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Experimental Details

Interventions

Intervention(s)
We conduct a survey to measure tax consent and the potential social, economic, and ideological factors that can affect it.

Participants in the treatment group are informed about France’s ranking on the Tax Complexity Index (https://www.taxcomplexity.org/), in comparison to neighboring European countries.
Intervention (Hidden)
The questionnaire used for the survey consists of 50 questions divided into 9 blocks.
The blocks are the following:
1) General knowledge and understanding of the tax system
2) Knowledge about individual tax situation
3) Treatment
4) Tax consent
5) Perception of difficulties in meeting tax obligations
6) Opinion on public spending
7) Perception of tax equity
8) Opinion on tax evasion
9) Interaction with fiscal administration

We use the tax complexity index built by Hoppe & al (2021). The Tax Complexity Index (TCI) measures the complexity of countries’ corporate income tax systems faced by multinational corporations. It builds on surveys of highly experienced tax consultants of the largest international tax services networks. The TCI is composed of a tax code subindex covering tax regulations and a tax framework subindex covering tax processes and features.
Hoppe, T., Schanz, D., Sturm, S., & Sureth-Sloane, C. (2021). The Tax Complexity Index – A Survey-Based Country Measure of Tax Code and Framework Complexity. European Accounting Review, 32(2), 239–273. https://doi.org/10.1080/09638180.2021.1951316
Intervention Start Date
2025-09-07
Intervention End Date
2025-09-30

Primary Outcomes

Primary Outcomes (end points)
The key outcome variables are the tax morale measures and directly come from specific questions in the survey. There are three tax consent measures:
1) Opinion on the overall level of taxes
2) Opinion on the personal level of taxes
3) Opinion on whether paying taxes is a “civic act”
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The survey will be conducted by a professional survey company among a representative sample of the French population.
The survey is structured as follows.
First step: the respondents answer a few questions about their knowledge and understanding about taxes.
Second step: participants are initially asked to rank France on the Tax Complexity Index within a sample of 64 countries (Europe, America and Asia).
Third step: participants are presented with France’s Tax Complexity Index ranking and asked to respond with both an open-ended and a closed-ended question regarding this ranking.
Fourth step: the respondents answer the questions that are used to construct the tax consent measures.
Fifth step: the respondents answer more questions on equity perception, economic behavior, tax evasion, and interactions with fiscal administration.
Experimental Design Details
We aim to use the information treatment as an instrument for the opinion on the complexity of the tax system and identify the causal effect of this variable on tax consent.
Randomization Method
Subjects will be randomly assigned to the treatment or control groups using blocks on sociodemographic characteristics (gender, age, socioeconomic status, city size) to ensure proper balance of these variables across experimental conditions.
Randomization Unit
0
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
No Cluster
Sample size: planned number of observations
3,000 people, 18+ years old
Sample size (or number of clusters) by treatment arms
1,500 control units / 1,500 treated units
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials