Generalizability of choice architecture interventions

Although a given choice architecture intervention (a ‘nudge’) can be highly effective in some conditions, it can be ineffective or counterproductive in others. Critically, researchers and practitioners cannot reliably predict which of these outcomes will happen on the basis of current knowledge. In this Review, we present evidence that the average effectiveness of choice architecture interventions on behaviour is smaller than often reported and that there is substantial heterogeneity in their effects. We outline the obstacles to understanding the generalizability of these effects, such as the complex interaction of moderators and their changes over time. We then clarify dimensions of generalizability and research practices (including systematic exploration of the moderators and practices designed to enhance generalizability) that could enable evidence on generalizability to be gathered more efficiently. These practices are essential for advancing nuanced theories of behaviour change and for more accurately predicting the effectiveness of choice architecture interventions across diverse populations, settings, treatments, outputs and analytical approaches. Choice architecture interventions (or ‘nudges’) aim to guide behaviour by changing the proximal physical, social or psychological environment. In this Review, Szaszi and colleagues show that the average effectiveness of these interventions is small and variable and outline how researchers can gather evidence defining this generalizability more efficiently.