Since the publication of “Nudge” by Thaler & Sunstein in 2008 and the resulting deluge of nudge interventions by governments, think tanks, and NGOs, public awareness of nudges has been ever increasing. Yet, little, if any, work has been done which seeks to understand the impact of nudge proliferation on nudge efficacy. The pilot CESS-Nuffield field subvention aims to add to our understanding of the long-term benefits of nudges by causally testing their effectiveness when knowledge of their existence is manipulated. In partnership with a charity, we will introduce an identity-based nudge and vary participant’s knowledge of its existence to investigate how knowledge affects the nudge’s efficacy. Our findings will shed light on the impacts of the plurality and long-term sustainability of nudges in the context of charitable giving. Further, our results will emphasize the need for better understanding of the nudge eco-system while informing our expectations of the future viability of nudge interventions in general.