Prediction markets are widely treated as forecasting devices that reveal collective expectations about uncertain futures. This article argues that under specifiable conditions they also function as coordination mechanisms: public probabilities that organize the behavior of voters, donors, journalists, traders, and institutions in ways that can be self-fulfilling or self-defeating. Most existing work asks whether prediction markets forecast accurately; this paper asks whether accurate forecasting is even the right criterion for a market that has become a public coordination device. Drawing on transaction-level evidence from the 2024 U.S. presidential election, we show that the social force of a market signal depends less on its size than on its persistence, the breadth of responding trader types, and cross-platform consensus. We introduce a Signal Credibility Index (SCI) -- combining the variance ratio VR(6), a two-sidedness diagnostic, and a trader-concentration adjustment -- as a microstructure-grounded criterion for predicting when price moves acquire behavioral traction. Applied to three major 2024 political shocks, the framework reveals that superficially similar events generated qualitatively distinct signal types with different implications for elite coordination. A cross-platform comparison establishes a systematic decoupling of social authority from epistemic robustness: the most visible market produced the least accurate forecasts. The framework carries direct implications for regulating prediction markets as democratic information infrastructure.

翻译：预测市场被广泛视为揭示对不确定性未来集体期望的预测工具。本文提出，在可指定的条件下，它们同样发挥协调机制的作用：公开概率通过组织选民、捐赠者、记者、交易者与机构的行为，可能产生自我实现或自我挫败的后果。现有研究多聚焦于预测市场能否精准预测；本文则追问，对于一个已成为公共协调机制的市场而言，精准预测是否仍是正确的评判标准。基于2024年美国总统大选的交易级数据，我们证明市场信号的社会影响力更多取决于其持续性、回应交易者类型的广度及跨平台共识，而非信号规模。我们提出信号可信度指数（SCI），该指数整合方差比率VR(6)、双边性诊断指标及交易者集中度调整项，构成基于微观结构的准则，用以预判价格变动何时具备行为牵引力。将该框架应用于2024年三大政治冲击事件的分析表明，表面相似的事件实际上产生了具有不同质的信号类型，对精英协调存在迥异影响。跨平台对比揭示了社会权威性与认知稳健性之间的系统性脱钩：曝光度最高的市场反而产生了最不准确的预测。该框架对将预测市场作为民主信息基础设施进行监管具有直接的政策启示。