Does the internet increase competition? To address this question, I exploit two institutional details unique to Germany: (1) Some municipalities received glass fibre cables that cannot be upgraded to DSL; I use these municipalities as a treatment group with reduced online competition. (2) German...

To investigate the external validity of laboratory results, we combine a public good experiment with three treatments in a field experiment. One treatment offers the opportunity to free-ride, the other two are placebo treatments. We compare results within subjects. In the free-riding treatment,...

Prices may differ between regional markets if transport capacities are limited. We develop a new approach to determine to which extent such differences stem from limited participation in cross-border trader, i.e. lack of integration, rather than from bottlenecks. This approach considers both...