Temporal analysis of cooperative behaviour in a blockchain for humanitarian aid during the COVID-19 pandemic

In the last few years, there has been a growing interest in the subject of blockchain technology for good. Among the many endeavours, blockchain technology has lately been exploited to build comple- mentary currencies in the sphere of humanitarian aid: currencies that support national economies to provide humanitarian aid and promote development. While there have been numerous research projects on complementary currencies (CCs) and their success, some critical aspects remain largely unexplored. First, even though cooperation is a key factor in the development of these systems, as local communities organize themselves in times of crisis, there is a lack of studies that investigate the cooperative behaviour in these systems and how it changes over time. Besides, there are only a few works studying these currencies during the recent crisis of the COVID-19 pandemic. In this work, we investigate Sarafu, a digi- tal complementary currency based on blockchain technology. To support cooperation, Sarafu implements a special type of account, the group account, thus allowing the study of cooperation groups, that cannot be easily analyzed in other CC systems; furthermore, it was successfully used for humanitarian aid during the COVID- 19 pandemic. We find that Sarafu users show strong cooperative behaviour, facilitated by the usage of these group accounts. Fur- thermore, we observe the increasing importance of cooperation groups over time, as well as differences over time in their spending behaviour. From the analysis, we highlight the presence of cooper- ation patterns and the importance of group accounts, a takeaway for current and future humanitarian projects.