Building a shield together: Addressing low vaccine uptake against cancer through social norms

We present the results of a large-scale field experiment designed to measure the effect of social norms on parents' decisions to vaccinate their daughters against the human papillomavirus (HPV) in Bogota, Colombia. Because low rates of HPV vaccine adoption are an issue in developed and underdeveloped countries alike, the use of standard social norm marketing strategies to foster vaccination can have the undesirable effect of reinforcing the status quo. In our experiment, parents were exposed to text messages that incorporated variations of static and dynamic social norms. We demonstrate that dynamic social norms and injunctive norms increased the vaccination rate by 23%. Interestingly, we also find that a version of static social norms that uses a loss frame is also effective in fostering vaccination, implying that policy-makers can also benefit from them. Against a common view among academics and practitioners, we found no evidence that static norms reinforce the status quo. Our results highlight the importance of crafting social norms interventions using dynamic and injunctive elements to foster vaccination in settings where the majority has not yet adopted the desired behavior.