Ever since Thaler and Sunstein published their influential book Nudge, the book and the theory it presents have received great praise and opposition. Nudge theory, and more particularly, nudging may be considered an additional strategy providing some novel instruments to the already rich governance toolbox. But what is its value? The current debates on Nudge theory are often highly normative or ideologically driven and pay limited attention to more practical aspects of the theory. Is nudging evaluable as a theory and a practice, and if so how? Is there solid evidence available of nudge success over other governance interventions? What is to be considered a nudge success? What data and evaluative techniques may assist in evaluating nudging beyond individual cases? The current article seeks to explore these questions.