Officially Mobilizing: Repeated Reminders and Feedback from Local Officials Increase Turnout

In the United States, voter turnout in many subnational elections is concerningly low. Campaigns and organizations have tested various interventions to increase turnout, but many are resource intensive and not feasible for local governments to implement equitably at scale. Here, we report a preregistered experiment with 1 million Philadelphia registered voters that is one such feasible intervention. Partnering with city officials, we sent postcards to some registrants before and after the spring 2019 municipal primary and before the November election, with the postprimary postcards thanking recipients for voting or saying "sorry we missed you." Others received postcards only before the November election. Receiving four postcards throughout the cycle increased November turnout by 1.5 percentage points; the two pregeneral postcards increased turnout by 0.8 percentage points. Importantly, mailers increased turnout without also exacerbating racial inequalities, providing scalable, easy-to-implement techniques for local governments to adopt.