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Nudging new entrants to the tax system to comply
Last registered on May 21, 2018

Pre-Trial

Trial Information
General Information
Title
Nudging new entrants to the tax system to comply
RCT ID
AEARCTR-0002962
Initial registration date
May 18, 2018
Last updated
May 21, 2018 11:51 AM EDT
Location(s)
Region
Primary Investigator
Affiliation
Australian National University
Other Primary Investigator(s)
Additional Trial Information
Status
Completed
Start date
2018-01-01
End date
2018-11-30
Secondary IDs
Abstract
The aim of this trial is to improve the communication of the Australian Taxation Office (ATO) with new entrants to the tax system to increase tax compliance. New entrants to the tax system have to lodge a tax return for the first time. The trial will evaluate the effectiveness of nudge letters that aim to create a positive and supportive first experience to encourage lodgement of a taxpayer's overdue tax return. The target population consists of individuals not in business who (based on data of the ATO) have never lodged an income tax return, have a requirement to lodge in 2017, have not lodged their 2017 income tax return, are new to the tax system in 2017 and would not otherwise be contacted by the ATO under existing risk treatments. Two treatments will be tested: (1) Treatment Group 1: individuals who receive a letter from the ATO stating that "We have not received your tax return"; (2) Treatment Group 2: individuals who receive a letter from the ATO stating "Welcome to the tax system - you need to lodge your first tax return" and providing details to help with the lodgement process. The treatments will be compared to a control group consisting of individuals who are not being contacted by the ATO. About 20,000 individuals were randomly assigned.
External Link(s)
Registration Citation
Citation
Sinning, Mathias. 2018. "Nudging new entrants to the tax system to comply ." AEA RCT Registry. May 21. https://doi.org/10.1257/rct.2962-2.0
Former Citation
Sinning, Mathias. 2018. "Nudging new entrants to the tax system to comply ." AEA RCT Registry. May 21. https://www.socialscienceregistry.org/trials/2962/history/29788
Sponsors & Partners

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Experimental Details
Interventions
Intervention(s)
Two treatments groups are considered: (1) Treatment Group 1: individuals who receive a letter from the ATO stating that "We have not received your tax return"; (2) Treatment Group 2: individuals who receive a letter from the ATO stating "Welcome to the tax system - you need to lodge your first tax return" and providing details to help with the lodgement process. The control group consists of individuals who are not being contacted by the ATO. Copies of sample letters are attached in "Docs & Materials" of this registration.
Intervention Start Date
2018-02-26
Intervention End Date
2018-05-04
Primary Outcomes
Primary Outcomes (end points)
Variables related to individual lodgement, reporting and payment behavior are the key outcome variables. A list of variables that will be provided by the ATO after the trial registration is attached in "Docs & Materials" of this registration. The main outcome variables are (original variable names in parentheses):
- Binary lodgement indicator
- Lodgment date (Form_Rcvd_Dt)
- Balance of assessment of the income tax return (Lodged_Balance_of_Assessment)
- Difference between predicted and lodged balance of assessment/declared cash income (Difference_BOA)
- Indicator for lodgment on paper or electronically (Chnl_Ctgry_Dcd)
- Indicator for amendment after lodgment (Amendment)
- Tax agent indicator (Ldgmt_Prprr_Typ)
- Lodgment through ATO online system (ATOOnline_Logon_Count_by_Date)
- Use of myTax (LU_Src_Lng_Dcd)
- New myTax registration (New_MyGov_Registration)
- Count of inbound calls relating to the letter / email (Inbound_Call_Count)
- Change in address can be observed (New_Postal_Address)
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
About 20,000 individuals were randomly assigned to two treatment groups and a control group.
Experimental Design Details
Randomization Method
A random list of the full population was created by the ATO using simple randomization.
Randomization Unit
Individual taxpayers.
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
About 20,000 individual taxpayers.
Sample size: planned number of observations
About 20,000 individual taxpayers.
Sample size (or number of clusters) by treatment arms
Treatment Group1: 9965 individuals; Treatment Group 2: 4296 individuals; Control Group: 3998 individuals.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Australian National University Human Ethics Committee
IRB Approval Date
2018-05-18
IRB Approval Number
2018/342
Analysis Plan

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Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
Yes
Intervention Completion Date
May 04, 2018, 12:00 AM +00:00
Is data collection complete?
Yes
Data Collection Completion Date
May 31, 2018, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
18259 individuals
Was attrition correlated with treatment status?
No
Final Sample Size: Total Number of Observations
18259 individuals
Final Sample Size (or Number of Clusters) by Treatment Arms
Treatment Group 1: 9965 individuals; Treatment Group 2: 4296 individuals; Control Group: 3998 individuals
Data Publication
Data Publication
Is public data available?
No
Program Files
Program Files
No
Reports and Papers
Preliminary Reports
Relevant Papers