Nudging the Trendsetters: Increasing Second-dose HPV Vaccination in Bogota, Colombia

This study investigates the effectiveness of dynamic norm nudges in promoting second-dose HPV vaccinations among trendsetters--parents who initiated the first-dose HPV vaccine for their daughters between 2017-2020. Utilizing administrative data from Bogota's Secretariat of Health in a field experiment, we measure the impact of various norm nudges, including trending, qualitative, and quantitative dynamic norms, on actual vaccination rates. Contrary to our hypothesis, dynamic norms alone fail to influence second-dose HPV vaccination rates for these trendsetters. However, the study reveals a 5.22 percent increase attributed to injunctive norms, representing a substantial 34 percent boost compared to the control groups 15.2 percent average. These findings underscore the importance of tailoring nudge strategies to the unique characteristics and preferences of the target population. This research significantly advances our understanding of norm-based interventions' efficacy in influencing minority behaviors, offering valuable insights for developing targeted and impactful public health strategies.