Abstract:

Crowdsourcing brings together crowdwisdom to realize open innovation. However， commercial practice of many crowdsourcing sites shows that the variations of users' abilities and submission quality are restricting its development. For example， China ’s leading crowdsourcing platform， ZhuBaJie， was established similarly to Taobao， but its development is obviously not comparable to e-commerce.Why do such awkward situations arise？ Compared with traditional outsourcing， crowdsourcing is known for its advantages of “low cost” and “low threshold”. In view of this， the requester's expectations of getting higher submission quality with fewer rewards and the user's motivation of experience out of rewards have become stronger. At the same time， crowdsourcing platforms often lower the participation threshold in pursuit of transactional popularity， which has led to a mix of “low-cost” requesters and “low-capacity” users. According to the classical information economics theory， under the influence of adverse selection caused by asymmetric information， the "high price" requesters and “high-capacity” users gradually withdrew， which resulting in a rapid increase in participation but a serious regression in submission quality.Existing research usually takes reserve quality （task requirement） as the sole criterion of rewards and ignores the willingness to pay of requesters， such as their expectation of getting higher submission quality with fewer rewards. The “reward size” of the requester in the all-pay auctions model， and endogenous reward are introduced by combine quality and payment expectation to explore the incentive effect of the reward size on crowdsourcsing.The difference between crowdsourcing and outsourcing is the word “crowd”. A large amount of literature describe the properties of users only in the individual perspective. The individual ability of the users and their group heterogeneity are focused on. By introducing “ability distribution” to describe the characteristics of requesters， it is found that the incentive effects of reward size may different in different directions， so the requesters need to adjust rewards according to user group’s characteristics.To explore the incentive effects of reward size and user groups’ ability distribution on crowdsourcing participation and submission quality， a single-prize crowdsourcing model in a simultaneous all-pay auction under incomplete information is built. It is found that： Firstly， users' optimal bidding strategies depend on their own abilities in all-pay context. Secondly， user groups’ heterogeneity determines the incentive effects of crowdsourcing. A higher reward induces significantly more participation and higher submission quality when the abilities of user group vary greatly. On the contrary， a higher reward decreases participation and submission quality. Lastly， depending on the variation of user groups’ ability distribution， the incentive effect may show different characteristics in different stages. A unique enlightenment for the operation of crowdsourcing sites is provided： participation and submission quality can not be achieved at the same time， trade-offs must be made to achieve optimal incentives.

Key words: crowdsourcing, reward size, ability distribution, incentive effects, all-pay auctions