Giulia Mascagni led a set of large-scale field experiments in Rwanda that sought to understand the determinants of tax compliance. The work was funded by the International Centre for Tax and Development (ICTD), in partnership with the African Tax Administration Forum (ATAF) and conducted in collaboration with the Rwanda Revenue Authority (RRA).
The project started with a comprehensive review of the growing literature on tax experiments, as research in this area has recently expanded from high income countries to middle-income countries. However, no experiments were yet available for any African or low-income country, in part due to the relatively recent modernisation of the relevant tax administration systems. Many questions remain unanswered about whether the key findings of the existing literature on tax experiments hold in the African context.
The researchers used administrative data from the Rwanda Revenue Authority to provide a comprehensive analysis of the Rwandan tax system, including quantifying audit probabilities, compliance gaps, and tax burdens, for which there was previously little evidence. The full set of results is available in the working paper “Unlocking the potential of administrative data: tax compliance and progressivity in Rwanda”.
Since no other tax experiment was available in the African continent, the researchers carried out a pilot experiment to gather some initial insights on tax compliance and to test the process of message delivery. The pilot sought to examine the effect of an information letter on whether or not taxpayers would voluntarily correct their tax declarations. The key results of the pilot relate both to the effectiveness of nudges to increase tax compliance and to lessons learned on how to implement this type of study in a low-income context.
Building on the experience of the pilot, the main, full-scale experiment sought to evaluate the effectiveness of different message contents and delivery methods in increasing compliance. The researchers used nine treatments, testing three different contents (deterrence, fiscal exchange, and a reminder) and delivery methods (SMS, email, letters). The full set of results is available in the forthcoming working paper “One size Does Not Fit All: A Field Experiment on the Drivers of Tax Compliance and Delivery Methods in Rwanda”.
A key component of the collaboration included building research capacity within the RRA and researchers from the RRA conducted their own investigation into taxpayers’ reactions to the messages of the experiment. The key results of this qualitative study are summarised in the forthcoming ICTD working paper “Communicating to Improve Compliance: Taxpayers’ Feedback on Messages and Modes of Delivery in Rwanda”.
Finally, the research team produced a summary brief for this project to summarise the outputs of the project, including the capacity building activities that occurred throughout. This brief is aimed at policymakers or anyone willing to get a high-level overview of the project