This paper explores the economic interactions within modern crowdsourcing markets. In these markets, employers issue requests for tasks, platforms facilitate the recruitment of crowd workers, and workers complete tasks for monetary rewards. Recognizing that these roles serve distinct functions within the ecosystem, we introduce a three-party model that distinguishes among the principal (the requester), the intermediary (the platform), and the pool of agents (the workers). The principal, unable to directly engage with agents, relies on the intermediary to recruit and incentivize them. This interaction unfolds in two stages: first, the principal designs a profit-sharing contract with the intermediary; second, the intermediary implements a mechanism to select an agent to complete the delegated task. We analyze the proposed model as an extensive-form Stackelberg game. Our contributions are threefold. First, we fully characterize the subgame perfect equilibrium of our model. In particular, the principal's contract design problem can be represented as virtual value pricing, a novel auction-theoretic formulation. We identify the optimality of linear contracts, even when the task has multiple outcomes and agents' cost distributions are asymmetric. Second, to quantify the principal's utility loss from delegation and information asymmetry, we introduce the price of double marginalization (PoDM) and the classical price of anarchy (PoA). We derive tight or nearly tight bounds on both ratios under regular and monotone hazard rate distributions. Finally, we extend our analysis to two natural variants of the base model: (i) the intermediary is restricted to anonymous pricing mechanisms, and (ii) the principal lacks precise information about the market size.

翻译：本文探讨了现代众包市场中的经济交互关系。在这些市场中，雇主发布任务请求，平台协助招募众包工作者，而工作者则通过完成任务获取报酬。认识到这些角色在生态系统中承担着不同功能，我们提出了一个区分委托方（任务发布者）、中介方（平台）与代理方集合（工作者）的三方模型。由于委托方无法直接与代理方互动，其必须依赖中介方进行人员招募与激励。该交互过程分为两个阶段：首先，委托方与中介方设计利润分享契约；随后，中介方实施机制以选定执行委托任务的代理方。我们将该模型构建为扩展式斯塔克尔伯格博弈进行分析。本文的贡献主要体现在三个方面：首先，我们完整刻画了模型的子博弈完美均衡特性。特别地，委托方的契约设计问题可表征为虚拟价值定价这一新颖的拍卖理论框架。我们证明了线性契约的最优性——即使任务存在多重可能结果且代理方的成本分布呈现非对称特征。其次，为量化委托方因委托关系与信息不对称导致的效用损失，我们引入了双重边际化代价与经典的无政府代价两个指标。在正则分布与单调风险率分布条件下，我们推导出这两个比率的紧界或近似紧界。最后，我们将分析拓展至基础模型的两个自然变体：（i）中介方被限制采用匿名定价机制；（ii）委托方缺乏关于市场规模的确切信息。