* This article is part of a broader project on tax compliance in Rwanda carried out in collaboration with the African Tax Administration Forum (ATAF) and the Rwanda Revenue Authority (RRA), with funding from the International Centre for Tax and Development (ICTD). We are extremely grateful to these institutions for the support they have provided throughout the project and especially to ATAF, which has played a vital role through the involvement of Dr Nara Monkam in the broader project. We are particularly thankful to the staff of the RRA for their invaluable inputs and assistance, that made this project possible. We would like to express our gratitude to RRA's officials, at the time of this project: Commissioner General Mr Richard Tusabe, Deputy Commissioner General Mr Pascal Ruganintwali, Deputy Commissioner for Research and Planning Mme Agnes Kanyangeyo, as well as other Deputy Commissioners who provided assistance and feedback throughout the project. Special thanks are due to RRA's Head of Research Mr Denis Mukama, who has coordinated the implementation of the project and has provided excellent inputs throughout the research. We are also very grateful to John Karangwa, Gaudence Uwimana, Lucie Niyigena, Naphtal Hakizimana, Florence Mukakabanda and the entire research and planning unit, as well as Mme Hajara Batamuliza and all officials involved in the letter delivery. This paper benefited from comments provided by Lucio Castro, Laura Paler, Jorge Garcia Hombrados, Carlos Scartascini, anonymous referees, and participants to various conferences and seminars. All remaining errors are our own. Declarations of interest: none.