F. Maxwell Harper, Xin Li, Yan Chen, and Joseph A. Konstan

Economic modeling provides a formal mechanism to under-stand user incentives and behavior in online systems. In this paper we describe the process of building a parameterized economic model of user contributed ratings in an online movie recommender system. We con-structed a theoretical model to formalize our initial understanding of the system, and collected survey and behavioral data to calibrate an em-pirical model. This model explains 34% of the variation in user rating behavior. We found that while economic modeling in this domain requires an initial nderstanding of user behavior and access to an uncommonly broad set of user survey and behavioral data, it returns significant formal understanding of the activity being modeled.

2005