Analysis of Behavioural Interventions' Spillover Effects on Individual Taxpayers Compliance: Evidence from Two Randomised Trials in Indonesia

Last registered on May 13, 2024

Pre-Trial

Trial Information

General Information

Title
Analysis of Behavioural Interventions' Spillover Effects on Individual Taxpayers Compliance: Evidence from Two Randomised Trials in Indonesia
RCT ID
AEARCTR-0013600
Initial registration date
May 13, 2024

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
May 13, 2024, 12:44 PM EDT

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

Locations

Region

Primary Investigator

Affiliation
The University of Sheffield

Other Primary Investigator(s)

PI Affiliation
The University of Sheffield
PI Affiliation
The University of Sheffield

Additional Trial Information

Status
On going
Start date
2024-01-01
End date
2024-08-31
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
Abstract
Behavioural interventions often create unintended effects on the other aspects of tax compliance that were not targeted during the design stage, or known as spillover effects. This study utilises data collected from two randomised controlled experiments that have been done in Indonesia to investigate the spillover effects that may arise from the interventions to annual income tax return compliance. In the previous experiments, we examined the impact of the interventions involving individual taxpayers. The sample consist of more than 51,000 taxpayer, where half of the sample were allocated to Control (status quo-received no treatment) and the other half to Treatment Group (received either physical letters or digital messages as the intervention). To investigate whether there are spillover effects from those two previous experiments, an instrumental variable regressions (IV) were used. The endogenous variables are instrumented by the initial random allocations to represent assuming that the taxpayers who although allocated to treatment group but in reality did not received the intervention would not be impacted by the treatments. This study could be a reference for policymakers when designing interventions. When designed should use the results as a reference when designing compliance-related interventions so it could cover a broader spectrum of tax compliance.
External Link(s)

Registration Citation

Citation
Gray, Daniel J., Matthew D. Rablen and Eko Arief Yogama. 2024. "Analysis of Behavioural Interventions' Spillover Effects on Individual Taxpayers Compliance: Evidence from Two Randomised Trials in Indonesia." AEA RCT Registry. May 13. https://doi.org/10.1257/rct.13600-1.0
Experimental Details

Interventions

Intervention(s)
We performed two field experiments consisting of just above 10,000 individual taxpayers in the first trial and around 41,000 individual taxpayers in the second trial. In both experiments, the sample is equally divided into Control and Treatment groups.
Intervention (Hidden)
Intervention Start Date
2024-01-01
Intervention End Date
2024-08-31

Primary Outcomes

Primary Outcomes (end points)
We analyse the effect of treatments targeting a certain aspect of tax compliance to the other aspects of taxes that might be affected. The primary outcome of this analysis is timely annual income tax return filing.
Primary Outcomes (explanation)
The primary outcome is timely annual income tax return filing measured by 0 if no or late income tax return and 1 if the annual income tax return is filed promptly.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
In the previous trials, the sample consist of just above 10,000 individual taxpayers in the first trial and around 41,000 individual taxpayers in the second trial. In both experiments, the sample is equally divided into Control and Treatment groups. The treatment in the first trial is sending physical letters accompanying a standard penalty notification form. The treatment in the second trial is digital messages broadcasted through WhatsApp reminding of the obligation to pay monthly income taxes.
Experimental Design Details
Randomization Method
The randomisations were performed using stratified randomisation based on several taxpayers' baseline characteristics.
Randomization Unit
Individual level randomisation.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
-
Sample size: planned number of observations
51,000 individual taxpayers.
Sample size (or number of clusters) by treatment arms
25,500 taxpayers are allocated to Control and 25,500 to Treatment.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
The Univbersity of Sheffield
IRB Approval Date
2022-11-06
IRB Approval Number
049945

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