Behavioural Responses to Tax administration changes

Last registered on October 17, 2023


Trial Information

General Information

Behavioural Responses to Tax administration changes
Initial registration date
September 01, 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 04, 2023, 6:55 AM EDT

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

Last updated
October 17, 2023, 9:00 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.



Primary Investigator


Other Primary Investigator(s)

PI Affiliation

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Tax administrations face continuos challenges to increase the efficiency of their daily activities. The existence of pre-populated forms allows the taxpayers carried out their tax duties since the direct costs of income tax compliance are non negligible for most of them.
However, this process requires some level of digital literacy that is not common in latin american countries. In this case, we are interested in assessing how behave the taxpayers under some different messages designed to encourage the use of a new personal income tax application. The setting includes two treatment groups based on the information provide to them.
External Link(s)

Registration Citation

Gamboa, Luis Fernando and Luis Carlos Reyes. 2023. "Behavioural Responses to Tax administration changes." AEA RCT Registry. October 17.
Experimental Details


The intervention consists of using the change in the accompanying mechanisms that taxpayers have to comply with their obligations. Consequently, three types of communications will be sent to three randomly selected groups. Each communication has a different level of information. The first one only reminds the date of compliance with income tax obligations. The second one also includes additional content on the implementation of a new accompanying interface and the specific date. The third letter includes, in addition to the content of the second letter, a set of images related to the new platform.
These letters will be sent before the due date of the tax liability and the implementation of the new accompanying technology.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Usage rate of the new interface, Average number of days prior to tax due date, average compliance, average difference in reported taxable income, average differences in tax payments
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experiment consists of dividing the income tax payer population into 4 groups. In three of them, a communication related to the date of fulfillment of obligations is sent with different levels of content.
In these letters, information is provided on the availability of a new support platform for compliance with the forms. The purpose of this intervention is to detect the usage rate of the new interface, the average number of days prior to tax due date and the average compliance under each scenario.
Experimental Design Details

The experiment includes 4 comparison groups of 32,939 tax payers:
Those who do NOT receive any communication (8,234)
Those who receive a basic reminder of the expiration date (8,228)
Those who receive a reminder of the due date + information on the implementation of the new support tool (8,280)
Those who receive a reminder of the due date + information on the implementation of the new image-based support tool (8,197)

The institution sends the letter to each taxpayer 3 weeks before the due date. At the end of the tax schedule, we will use the administrative registries from the use of the interfase and the amount of money reported (income and taxes) to disentangle the differences among each others.
Randomization Method
Randomization done by computer using the taxpayer database.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
About 33,000 individuals
Sample size: planned number of observations
33000 individuals
Sample size (or number of clusters) by treatment arms
8,228 tax payers belong to the control group, Treatment 1 includes 8,228 tax payers), treatment 2 (Those who receive a reminder of the due date + information on the implementation of the new support tool, 8,280 taxpayers), Tretment 3 (Those who receive a reminder of the due date + information on the implementation of the new image-based support tool, 8,197 taxpayers)
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


Post Trial Information

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials