Keep It Simple: A Field Experiment on Information Sharing in Social Networks
SMS information campaigns are increasingly used for policy. To investigate their effectiveness, we conduct a lab-in-the-field experiment to study information sharing through mobile phone messages. Subjects are rural households in Mozambique who have access to mobile money. In the base treatment, subjects receive an SMS containing information on how to redeem a voucher. They can share this information with other exogeneously assigned subjects. We find that few participants redeem the voucher. They nonetheless share it with others and many share information they do not use themselves. Information is shared more when communication is anonymous and we find no evidence of homophily in information sharing. We introduce treatments to vary the cost of sending a message, shame those who do not send the voucher to others, or allow subjects to appropriate the value of information. All decrease information sharing. To encourage information sharing, the best is to keep it simple.
We benefited from comments from Yves Zenou, Sanjeev Goyal, Francis Bloch, Markus Goldstein, and participants to the Monash University Conference on Social Networks 2018. We wish to thank Stefan Leeffers, Timoteo Simone, and the NOVAFRICA office in Mozambique for excellent research assistance. We are particularly grateful to Carteira Movel/Mkesh for institutional support. We wish to acknowledge financial support from the International Growth Centre. IRB approval was secured with Universidade Nova de Lisboa. None of the authors has financial or institutional affiliation with Carteira Movel/Mkesh. All errors are our responsibility. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.