5 Conclusion and Discussion
This paper presents the results obtained from two natural field experiments that were conducted in collaboration with the Australian Taxation Office (ATO). The first trial was designed to test the effect of four non-deterrence interventions (modified versions of a letter that the ATO sends to businesses if their reported transactions vary considerably from normal business activity) on response rates, the timing of payments and the amount of payments of liabilities. Our empirical findings reveal that the four treatments (timing, social norms, change in color, warm glow) did not have a significant effect on any of the outcome measures considered in our analysis.
The aim of the second trial was to improve internal procedures and engagement strategies with taxpayers. The trial consists of two parts. The first part assesses the effect of changing internal guidelines used by field auditors to raise awareness of the relevance of tax debt payments. The second part focuses on studying the effect of changing the script that desk auditors use for phone conversations and simplifying a follow-up letter to businesses. Outcome variables include debt collection measures, the duration of case cycles, and a variable indicating whether a default assessment was raised by the ATO during the audit (which happens when businesses do not comply with their filing obligations and means high fines for the affected taxpayer).