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Behavioral insights and tax compliance: Experimental evidence from Belgium
Last registered on August 31, 2015

Pre-Trial

Trial Information
General Information
Title
Behavioral insights and tax compliance: Experimental evidence from Belgium
RCT ID
AEARCTR-0000827
Initial registration date
August 31, 2015
Last updated
August 31, 2015 2:31 PM EDT
Location(s)
Region
Primary Investigator
Affiliation
University of Oxford
Other Primary Investigator(s)
PI Affiliation
London School of Economics
Additional Trial Information
Status
In development
Start date
2015-09-01
End date
2016-09-01
Secondary IDs
Abstract
We aim to study the effect of nudges in reminder letters at two different stages of the tax cycle. In collaboration with the Ministry of Finance of Belgium, we are designing an RCT on Belgian taxpayers that are either late with their tax payment or that have not filed their tax return. For the trial on the late payment reminder we will circulate 8 treatment letters in addition to the current control letter. These treatment letters introduce the following nudges: (1) simplification; (2) social norm; (3) public goods (positively framed); (4) public goods (negatively framed); (5) social norm + public goods; (6) active choice; (7) explicit penalty; and (8) active choice + explicit penalty. For the trial on the late filing reminder the following 3 treatment letters will be circulated in addition to a simplified control letter: (1) social norm; (2) public goods; (3) social norm + public goods. The nudges that we introduce in these reminder letters are grounded in behavioral insights such as loss aversion (positive vs. negatively framed public goods letters), social preferences (social norm letter), and status quo bias (active choice letter). We aim to treat the universe of late tax filers and late taxpayers in Belgium. The last two digits of the national identity number will be used to randomly assign treatment letters across the population. All treatment and control groups have equal size (in terms of number of letters sent out). The outcome variables will include tax payments, timing of payment, and number of filers and we will analyse heterogeneous treatment effects across taxpayers with different characteristics including gender, income, age, job status (employee or self-employed), region, online or paper filing. We also aim to convince the tax administration to send out new letters in a second year in order (1) to further validate the heterogeneous treatment effects using the first-year results to determine the random allocation to treatment and (2) to evaluate the persistence of the treatment effects.
External Link(s)
Registration Citation
Citation
De Neve, Jan-Emmanuel and Johannes Spinnewijn. 2015. "Behavioral insights and tax compliance: Experimental evidence from Belgium." AEA RCT Registry. August 31. https://doi.org/10.1257/rct.827-1.0.
Former Citation
De Neve, Jan-Emmanuel and Johannes Spinnewijn. 2015. "Behavioral insights and tax compliance: Experimental evidence from Belgium." AEA RCT Registry. August 31. https://www.socialscienceregistry.org/trials/827/history/5144.
Experimental Details
Interventions
Intervention(s)
Intervention Start Date
2015-09-01
Intervention End Date
2016-09-01
Primary Outcomes
Primary Outcomes (end points)
The outcome variables will include tax payments, timing of payment, and number of filers and we will analyse heterogeneous treatment effects across taxpayers with different characteristics including gender, income, age, job status (employee or self-employed), region, online or paper filing. We also aim to convince the tax administration to send out new letters in a second year in order (1) to further validate the heterogeneous treatment effects using the first-year results to determine the random allocation to treatment and (2) to evaluate the persistence of the treatment effects.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We aim to study the effect of nudges in reminder letters at two different stages of the tax cycle. In collaboration with the Ministry of Finance of Belgium, we are designing an RCT on Belgian taxpayers that are either late with their tax payment or that have not filed their tax return. For the trial on the late payment reminder we will circulate 8 different treatment letters in addition to the current control letter. These treatment letters introduce the following nudges: (1) simplification; (2) social norm; (3) public goods (positively framed); (4) public goods (negatively framed); (5) social norm + public goods; (6) active choice; (7) explicit penalty; and (8) active choice + explicit penalty. For the trial on the late filing reminder the following 3 treatment letters will be circulated in addition to a simplified control letter: (1) social norm; (2) public goods; (3) social norm + public goods.
Experimental Design Details
Randomization Method
The last two digits of the national identity number will be used to randomly assign treatment letters across the population. All treatment and control groups have equal size (in terms of number of letters sent out).
Randomization Unit
Individual taxpayers.
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
0
Sample size: planned number of observations
We aim to treat the universe of late tax filers and late taxpayers in Belgium.
Sample size (or number of clusters) by treatment arms
Our partners at the Ministry of Finance have indicated that the number of observations per treatment arm would be approximately 50,000 individuals.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
IRB Approval Date
IRB Approval Number
Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
No
Is data collection complete?
Data Publication
Data Publication
Is public data available?
No
Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers