Signature requirements for initiatives

Signature requirements serve as barriers to prevent citizens from overusing initiatives. This study investigates the properties of optimal signature requirements by proposing a model in which the initiative process is a game played among citizens, a campaigner, and a legislature. Under the optimal requirement, the campaigner succeeds in collecting the required signatures only when it creates welfare that exceeds the cost of holding a referendum for the final decision. I specify the condition that such an optimal requirement is achievable. In addition, I perform comparative statics analyses to investigate the validity of the differences in signature requirements among countries and petition types. The results reveal a high optimal requirement when citizens have low variance regarding their opinions or do not consider the campaigned issue important. Finally, I evaluate the suggested reforms in the real world, such as imposing an additional cost on the campaigner to initiate a petition and a ban on paid petitioners, and show that while the former reduces citizen welfare, the latter improves it