Evidence from a Survey Experiment on Undeclared Work in Italy and Spain

Last registered on September 21, 2026
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Pre-Trial

Trial Information

General Information

Title
Evidence from a Survey Experiment on Undeclared Work in Italy and Spain
RCT ID
AEARCTR-0019446
Initial registration date
September 16, 2026

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 21, 2026, 10:28 AM EDT

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

Locations

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Primary Investigator

Name
Thomas Martin
Affiliation
Department of Economics, University of Warwick
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Other Primary Investigator(s)

PI Name
Zouhair Ennaoumi
PI Affiliation
University of Salerno
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PI Name
Roberto Dell'Anno
PI Affiliation
University of Salerno
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PI Name
Lavinia Parisi
PI Affiliation
University of Salerno
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PI Name
Laura Fumagalli
PI Affiliation
ISER, University of Essex
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Additional Trial Information

Status
In development
Start date
2026-08-17
End date
2026-09-30
Keywords
Labor, Welfare
Additional Keywords
JEL code(s)
C83, C99, D83, H26, J32, J46
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Undeclared work remains widespread in many countries and has important consequences for workers, employers and society. Decisions about whether and how much employment to declare may depend on the perceived costs and benefits of declaration and the institutional circumstances in which these decisions are made.

We study how people think about employment declaration decisions involving workers and employers in Italy and Spain. We first measure beliefs and views about the costs and benefits of declared and undeclared employment. We then use a randomized information experiment to test whether providing information about these costs and benefits affects beliefs and decisions.
External Link(s)

Registration Citation

Citation
Dell'Anno, Roberto et al. 2026. "Evidence from a Survey Experiment on Undeclared Work in Italy and Spain." AEA RCT Registry. September 21. https://doi.org/10.1257/rct.19446-1.0
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2026-08-17
Intervention End Date
2026-09-30

Primary Outcomes

Primary Outcomes (end points)
1. Worker declaration preferences: Number of hours respondents consider advantageous to declare from the worker’s perspective, considering monetary factors and all factors.

2. Employer declaration preferences: Number of hours respondents consider advantageous to declare from the employer’s perspective, considering monetary factors and all factors.

3. Relative worker–employer influence: Respondents’ assessment of the relative influence of the worker and employer over the declaration decision.

4. Final declaration outcome: Number of hours respondents expect to be officially declared in the final employment agreement.

5. Policy demand: Respondents’ support for policies aimed at reducing undeclared work and encouraging declared employment.

6. Behavioural outcomes: Respondents’ willingness to engage with a petition related to undeclared work and to view informational video material related to declared employment.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The study is an individually randomized online survey experiment conducted in Italy and Spain. Respondents consider hypothetical employment situations involving decisions about declared and undeclared work. We first elicit baseline beliefs and views before randomly assigning respondents to different information conditions.

Following the information intervention, we measure beliefs and decisions concerning employment declaration. Respondents subsequently consider changes in the broader institutional environment, after which we examine how their beliefs and decisions respond. The survey also measures broader views about undeclared work and related policies.
Experimental Design Details
Not available
Randomization Method
Randomization is conducted by computer within the online survey platform (Qualtrics). Respondents are randomly assigned at the individual level to one of three experimental conditions (with equal probability), with randomization conducted separately within Italy and Spain.
Randomization Unit
Randomised at the individual level.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
no clusters
Sample size: planned number of observations
Approximately 4,500.
Sample size (or number of clusters) by treatment arms
Each country has 2250 observations and each of the three treatment arms and randomised with equal probability so roughly 750 observations in each arm.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
With approximately 4,500 respondents, split roughly equally between Italy and Spain and randomized approximately equally across three treatment arms within each country, the study is powered to detect pairwise treatment effects of approximately 0.15 standard deviations within each country and approximately 0.10 standard deviations in the pooled sample, assuming 80% power and a two-sided 5% significance level. Treatment is randomized at the individual level and is not clustered.
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Comité de Ética de la Investigación (CEI-UAM)
IRB Approval Date
2026-04-24
IRB Approval Number
CEI-153-3745
Analysis Plan

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