Default clinic appointments promote influenza vaccination uptake without a displacement effect

The majority of U.S. adults do not receive an annual influenza vaccination. Behavioral economics tools can be harnessed to encourage health behaviors. Specifically, scheduling patients by default for a flu shot appointment leads to higher vaccination rates at a medical practice than does merely encouraging flu shot appointments. It is not known, however, whether default appointments actually increase net vaccination or merely displace vaccinations from other venues. In the current field experiment, we examined the use of default appointments in a large medical practice and established that automatically scheduled appointments increased the total vaccination rate by 10 percentage points within the practice without displacing vaccinations that patients would otherwise have received in other settings. This increased vaccination rate came at the cost of a high no-show rate. These findings point to an effective way to increase vaccination rates and may offer a cost-saving measure in the scope of accountable care organizations.