报告题目：A Model of Click-farming

报告人：中国政府管制研究院 甄艺凯 博士

报告时间：2016年12月22日晚上18点

报告地点：bevictor伟德6号楼210室

组织发起：bevictor伟德前沿文献与经典著作读书会

主办单位：bevictor伟德

协办单位：科研处

内容摘要：

To a certain kind of firms, their decision variables are different from traditional variables such as price and R&D. These decision variables impact profits of firms by changing consumer belief and behavior. As the internet business model is fully integrated into the economic life of the general public, a plenty of these decision variables become endogenous. Taking “click farming” as an example, this paper studies decision-making motives of “click farming”, equilibrium, and the impact on social welfare. Consider there are two types of consumers: sophisticated consumers that can differentiate the quality of products and naïve consumers that determine the quality of products by click farms. There are two firms: one produces qualified products and the other produces fake and inferior products. This paper builds a model and proves that: there does not exist a pure-strategy Nash equilibrium of “click farms”, whereas there exists a mixed-strategy Nash equilibrium with asymmetric (the high-quality firm has mass points at its lower bound) continuous distribution. On the basis of equilibrium results, we find that click farming behavior of firms push up the average price of the market. And by comparative statics, this paper analyzes the relationship between “click farms”of firms and net social surplus of products, and analyzes the difference between the costs of the high-quality firm and the costs of the low-quality firm. Finally, calculate and analyze the total social welfare under this market structure.

参考文献：

[1] Kyle Bagwell and Michael H. Riordan. High and Declining Prices Signal Product Quality[J]. American Economic Review, 1991, 81(1):224-239.

[2] Armstrong, M. and Yongmin Chen.“Inattentive Consumers and Product Quality,” Journal of the European Economic Association, 2009, 7(2-3): 411-422.

[3] Butters, G.R. “Equilibrium Distributions of Sales and Advertising Prices”, Review of Economics Studies, 1977, 44(3):465-491.

[4] Grossman, G.M, and C. Shapiro. “Informative Advertising with Differentiated Products”, Review of Economic Studies, 1984,51(1):63-81.

[5] Janssen, M. and M.C. Non.“Going where the Ad Leads You: On High Advertised Prices and Searching Where to Buy”，Marketing Science, ,2009, 28(1):87-98.

[6] Milgrom P, Roberts J. Price and Advertising Signals of Product Quality[J]. Journal of political Economy, 1986, 94(4):796-821.

[7] Salop, S. and J. Stiglitz. “Bargains and Ripoffs: A Model of Monopolistically Competitive Price Dispersion”, Review of Economics Studies, 1977, 44(3):493-510.

[8] Rosenthal, R.W. “A Model in Which an Increase in the Number of Sellers Leads to a Higher Price”, Econometrica, 1980, 48(6):1575-1579.

[9] Varian, Hal R. “A Model of Sales”, American Economic Review, 1980,70(4): 651-659

[10]Stahl, D.O.“Oligopolistic Pricing with Sequential Consumer Search”，American Economic Review, 1989, 79(4):700-712.

[11]Narasimhan, C. “Competitive Promotional Strategies”, Journal of business, 1988, 61(4):427-449.

[12]Janssen, M. and J.L. Moraga-González. “Strategic Pricing, Consumer Search and the Number of Firms”, Review of Economics Studies, 2004,71(4):1089-1118.

[13]Janssen, M., J.L. Moraga-González and M.R. Wildenbeest.“Truly Costly Sequential Search and Oligopolisitic Pricing”，International Journal of Industrial Organization, 2005, 23(5):451-466.

[14]Chen Yongmin and T. Zhang. “Equilibrium Price Dispersion with Heterogeneous Searchers “, International Journal of Industrial Organization, 2011, 29(6):645-654.

[15]Akerlof.G.A.“The Market for “lemons”: quality uncertainty and market mechanism”, Quarterly Journal of Economics, 1970, 84(3):488-500.