Replication Data for: Instrumenting Beliefs in Threshold Public Goods

Understanding the causal impact of beliefs on contributions in Threshold Public Goods (TPGs) is particularly important since the social optimum can be supported as a Nash Equilibrium and best-response contributions are a function of beliefs. Unfortunately, investigations of the impact of beliefs on behavior are plagued with endogeneity concerns. We create a set of instruments by cleanly and exogenously manipulating beliefs without deception. Tests indicate that the instruments are valid and relevant. Perhaps surprisingly, we fail to find evidence that beliefs are endogenous in either the one-shot or repeated-decision settings. TPG allocations are determined by a base contribution and beliefs in a one shot-setting. In the repeated-decision environment, once we instrument for first-round allocations, we find that second-round allocations are driven equally by beliefs and history. Moreover, we find that failing to instrument prior decisions overstates their importance.

探究信念对门槛公共物品（Threshold Public Goods, TPGs）中贡献行为的因果影响具有重要意义，因为社会最优解可作为纳什均衡（Nash Equilibrium）被支撑，且最优反应贡献额是信念的函数。遗憾的是，有关信念对行为影响的研究往往面临内生性困扰。我们通过无欺骗的方式精准且外生地操纵信念，构建了一组工具变量。检验结果表明，该工具变量兼具有效性与相关性。或许令人意外的是，无论是单次决策场景还是重复决策场景，我们均未发现信念存在内生性的证据。在单次决策场景中，门槛公共物品的贡献额度由基础贡献额与信念共同决定。在重复决策环境下，当我们为首轮贡献额度引入工具变量后，发现第二轮贡献额度同时由信念与历史行为均等驱动。此外，我们发现若未对前期决策引入工具变量，则会高估其对后续行为的影响权重。