Control experiment for health center users to compare the usage of hand sanitizers through nudges during the COVID-19 pandemic in Japan

To assess the effectiveness of promoting hand hygiene by nudges, the control experiment was conducted during the COVID-19 pandemic in Japan. Hand sanitizers were placed at entrances of health centers A (nudge group) and B (non-nudges/reference group). The users of each group were approximately 40 daily. In the nudge group, during week 1, the conventional notice was displayed. From weeks 2 to 4, sequential nudges based on the framework “MINDSPACE” were implemented: drawing an arrow on the floor towards a hand sanitizer, posting altruism messages, and providing trends in hand sanitizer usage. From weeks 5 to 8, no additional interventions were implemented. Until week 4, usage in the nudge group increased steeply. Although the gap narrowed after week 5, usage in the nudge group (1.7 times of week 1 usage) was higher than that in the reference group (1.4 times of week 1 usage) at week 8. The nudges cost 0.9 USD and were prepared within 3 hours. The series of nudges can be implemented with low cost and short preparation time, and the effect may last until week 8; these nudges will meet practitioners’ needs during the COVID-19 pandemic.