Do birds of a feather flock together? Platform’s quality screening and end-users’ choices theory and empirical study of online trading platforms

We propose a model which incorporates both quality and quantity in end-users’ interactions and analyze how platforms can use quality screening to alleviate information asymmetry and motivate end-users’ participations. We address the question from theoretical and empirical perspectives. In the theory, we build a model in which two platforms compete but only one of them screens sellers’ products. We show that the quality screening influences consumers’ expectations of product quality and their choices of sellers and platforms. The resulting screening effect, together with the network and competition effects, further drives sellers to enter different platforms. The equilibrium result indicates that sellers’ incentives to join the platform that screens products follow a non-monotonic relationship with respect to the observable quality of products. We estimate the model in Alibaba’s Platforms - Tmall and Taobao. The results are consistent with the theory. Counterfactual analysis suggests quality screening benefits consumers and Alibaba.