This paper attempts to shed light on the pricing behaviour of firms or sellers in market places with price competition. In particular, it aims at testing the mechanism that lies at the heart of one of the most famous models in economics, namely the Bertrand model of competition. This model...

We analyze the relationship between unemployment and the supply of online labor for microtasking. Using detailed US data from a large microtasking platform between 2011 and2015, we study the participation and the number of hours supplied by workers in the US.We find that more individuals...

Missing values are a major problem in all econometric applications based on survey data. A standard approach assumes data are missing-at-random and uses imputation methods, or even listwise deletion. This approach is justified if item non-response does not depend on the potentially missing...

Do contributions to online content platforms induce a feedback loop of ever more user-generated content or will they discourage future contributions? To assess this, we use a randomized field experiment which added content to some pages in Wikipedia while leaving similar pages unchanged. We find...

When contributing content on large online platforms, producers of user-generated content have to decide where to contribute. On a complex and dynamic platform like wikipedia, this decision is expected to depend on the way the content is organized. We analyse whether the hyperlinks on Wikipedia...

We analyze whether an informal second channel for communication can improve the efficiency of knowledge transfer in an electronic network of practice. We explore this question by analyzing the effect of chat rooms in the well-known Q&A forum Stack Overflow. We identify the causal effect using a...

We study the role of privacy in the market for mobile applications. For such programs used with smartphones and tablet PCs a very important market has emerged. Yet, neither the role of privacy on that market is well understood, nor do we have empirical evidence regarding its role therein. We...

I quantify spillovers of attention in a network of content pages, which is challenging, because such networks form endogenously. I exploit exogenous variation in the article network of German Wikipedia to circumvent this problem. Wikipedia prominently advertises one featured article on its main...

Are there positive or negative externalities in knowledge production? We analyze whether current contributions to knowledge production increase or decrease the future growth of knowledge. To assess this, we use a randomized field experiment that added content to some pages in Wikipedia while...

Policy makers are increasingly concerned about the combination of market power and massive data collection in digital markets. This concern is fueled by the theoretical prediction that more market power causes firms to collect ever more data from their users. We investigate the relationship...