On the Posted Pricing in Crowdsourcing: Power of Bonus.

In practical crowdsourcing systems such as Amazon Mechanical Turk, posted pricing is widely used due to its simplicity, where a task requester publishes a pricing rule a priori, on which workers decide whether to accept and perform the task or not, and are often paid according to the quality of their effort. One of the key ingredients of a good posted pricing lies in how to recruit more high-quality workers with less budget, for which the following two schemes are considered: (i) personalized pricing by profiling users in terms of their quality and cost, and (ii) additional bonus payment offered for more qualified task completion. Despite their potential benefits in crowdsourced pricing, it has been under-explored how much gain each or both of personalization and bonus payment actually provides to the requester. In this paper, we study four possible combinations of posted pricing made by pricing with/without personalization and bonus. We aim at analytically quantifying when and how much such two ideas contribute to the requesteru0027s utility. To this end, we first derive the optimal personalized and common pricing schemes and analyze their computational tractability. Next, we quantify the gap in the utility between with and without bonus payment in both pricing schemes. We analytically prove that the impact of bonus is negligible significantly marginal in personalized pricing, whereas crucial in common pricing. Finally, we study the notion of Price of Agnosticity that quantifies the utility gap between personalized and common pricing policies. This implies that a complex personalized pricing with privacy concerns can be replaced by a simple common pricing with bonus. We validate our analytical findings through extensive simulations and real experiments done in Amazon Mechanical Turk, and provide additional implications that are useful in designing a pricing policy.