Beyond the Targeted Customer: Spillover Effect through Social Influence

Following an innovative large-scale field experiment, this study measures the extent of the spillover effect through social influence in a social advertising campaign. Results show that, even when the campaign does not have a significant direct effect on targeted customers, it still creates a significant spillover effect on targets’ peers because of social influence. The spillover effect is achieved through weak ties (acquaintances) rather than strong ones (close relationships). For social advertising, it may be more effective to target those with broad weak connections rather than those with strong ties.