In this thesis, I contribute new empirical evidence to address, under which circumstances nudges provide a promising tool for evidence-based policy design and what challenges this brings about. Nudges are interventions that alter the decision environment of individuals in a way that makes particular choices easier while not taking any options or altering their economic costs. Nudge-interventions have become popular among policy makers because they are perceived as less intrusive as other policy measures and implementation costs are low. The thesis comprises four self-contained chapters. Chapter 2 presents a systematic review of the effects of nudges on energy consumption by private households. Chapters 3 and 4 consecutively add results from own experimental field tests of nudges applied to business taxation and online education. Chapter 5 analyzes the status quo of research cooperations between academic researchers or nudge units on the one hand, and public partners on the other.