Stronger Police Don’t Just Improve Service — They Discourage Vigilante Justice

A field experiment in South Africa shows that increasing the state's ability to locate households reduces citizens' readiness to take part in mob vigilantism.

🔎 How the field experiment worked

Households were randomly made more legible to police—that is, the police's capacity to locate specific households was experimentally varied. Surveys were conducted several months after the intervention to measure changes in attitudes and intended behavior. An additional randomized information experiment probed why those changes occurred.

📈 Key findings

• Households that became more legible to police reported greater willingness to rely on police rather than informal punishment.
• The same households reported lower willingness to participate in vigilantism in follow-up surveys conducted several months after the intervention.
• Evidence from the supplemental information experiment points to increased fear of state punishment for engaging in vigilantism as the more likely mechanism, rather than improvements in perceived police service quality.

💡 Why it matters

These results imply that citizens' cooperation with capable state institutions can arise not only from satisfaction with services but also from the state's ability to limit alternative actions (for example, by making vigilantism riskier). This distinction matters for understanding how state capacity shapes public behavior and for designing interventions aimed at reducing informal justice practices.