Interaction effects capture the impact of one explanatory variable x1 on the marginal effect of another explanatory variable x2. To explore interaction effects, socalled interaction terms x1x2 are typically included in estimation specifications. While in linear models the effect of a marginal...

This article revisits an analysis by Frondel, Ritter and Schmidt (2008) of Germany's Renewable Energy Act, which legislates a system of feed-in tariff s to promote the use of renewable energies. As in the original article, we argue that Germany's support scheme subsidizes renewable energy...