Document Type

Technical Report

Publication Date


Technical Report Number



New forms of production based in electronic technology, such as open-source and open-content production, convert private commodities (typically software) into essentially public goods. A number of studies find that, like in other collective goods, incentives for reputation and group identity motivate contributions to open source goods, thereby overcoming the social dilemma inherent in producing such goods. In this paper we examine how contributor motivations affect the quality of contributions to the open-content online encyclopedia Wikipedia. We find that quality is associated with contributor motivations, but in a surprisingly inconsistent way. Registered users' quality increases with more contributions, consistent with the idea of participants motivated by reputation and commitment to the Wikipedia community. Surprisingly, however, we find the highest quality from the vast numbers of anonymous "Good Samaritans" who contribute only once. Our findings that Good Samaritans as well as committed "zealots" contribute high quality content to Wikipedia suggest that it is the quantity as well as the quality of contributors that positively affects the quality of open source production.


A preliminary version of this paper was published online in November 2005.