Evidence-based policies, nudge theory and Nancy Cartwright: a search for causal principles

Abstract

Abstract Nancy Cartwright argues that evidence-based policies should not only rely on randomized controlled trials (RCTs) to test their effectiveness – they should also use horizontal and vertical searches to find support factors and causal principles that help define how those policies work. This paper aims at analyzing Cartwright's epistemology regarding evidence-based policies and their use of RCTs while applying her findings to current research involving nudges as behavioral public policy interventions. Holding a narrowly instrumental view of rationality, nudge theory tends to neglect other expressive components. Policymakers, in their quest for causal principles, should consider the expressive rationality of individuals in their research. This inclusion would not only increase the effectiveness of nudges, but also address some ethical issues related to people's autonomy when targeted by these interventions.