In the public projects problem, a group of decisionmakers aggregate their preferences to choose one alternative. Recent work on public projects has proposed the Quadratic Transfers Mechanism (QTM) and shown asymptotic welfare guarantees in some cases. We begin by giving new non-asymptotic Price of Anarchy guarantees for the QTM. We then incorporate an alternative philosophy toward group decisionmaking, aggregation of information about which is the best alternative. We propose a public projects mechanism based on the QTM that aggregates both preferences and predictions, modeled as forecasts of the projects' welfare impacts. When the predictions come from a prediction market or wagering mechanism, we show the entire mechanism is robust to manipulation and give Price of Anarchy guarantees, though under strong assumptions on the mechanism's knowledge. Our results focus primarily on the case of deciding between two alternatives, showing the Price of Anarchy tends to $1$ as natural measures of the "size" of the population grow large. In most cases, the mechanisms achieve a balanced budget as well.

翻译：在公共项目问题中，一组决策者聚合其偏好以选择某个备选方案。近期关于公共项目的研究提出了二次转移机制（QTM），并展示了在某些情况下的渐近福利保证。我们首先给出了QTM的非渐近无政府状态价格保证。然后，我们引入了一种针对群体决策的替代理念——关于哪个备选方案最优的信息聚合。我们提出了一种基于QTM的公共项目机制，该机制同时聚合偏好与预测（预测被建模为对项目福利影响的预估）。当预测来自预测市场或押注机制时，我们证明整个机制对操纵具有鲁棒性，并给出了无政府状态价格保证，尽管这依赖于对机制知识的强假设。我们的结果主要聚焦于在两个备选方案间进行决策的情况，表明当衡量群体“规模”的自然测度增大时，无政府状态价格趋近于1。在多数情况下，该机制还能实现预算平衡。