Seeing the nudge from the trees: The 4S framework for evaluating nudges

Nudging is a popular and influential approach in policymaking. Yet, it has faced substantial criticism from several policy perspectives, with growing concern raised about the efficacy of some nudge interventions. This article offers an evaluative framework for nudging which captures these various perspectives. Our 4S framework highlights the importance of nudges being sufficient, scalable, and subjective, in addition to being statistically significant, to be an effective policy response. We review various nudge interventions, coupled with various methodological critiques, to demonstrate the need for a more expansive evaluative framework. The 4S framework synthesizes these sizeable literatures and numerous critiques to meet this need, serving as an important contribution to behavioral policymakers. We argue that the 4S framework complements existing frameworks for designing behavioral interventions as an evaluative framework. By adopting the 4S framework, policymakers will be better placed to design interventions which are effective in relation to the wider policy environment.