Reminders Work, but for Whom? Evidence from New York City Parking Ticket Recipients

We investigate heterogeneity in responsiveness to reminder letters among New York City parking ticket recipients. Using variation in the timing of letters, we find a strong aggregate response. But we find large differences across individuals: those with a low baseline propensity to respond to tickets—a natural nudge target—react least to letters. These low-response types, who incur significant late penalties, disproportionately come from already disadvantaged groups. They do react strongly to traditional, incentive-based interventions. We discuss how accounting for response heterogeneity might change one’s approach to policy and how one might use our analysis to target interventions at low-response types.