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 exogenously 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.