Firms and policy makers use behavioral interventions to promote sustainable development in a variety of domains. Doing it effectively requires adopting multiple interventions and evaluating their impacts on behavior and satisfaction. Currently, there is limited evidence of the direct and indirect effects of nudges that target one domain and of the effectiveness of multi-domain nudges, leading to potential misestimation of the cost-effectiveness of this type of intervention and poor guidance on how to design them best.
Through a large-scale randomized controlled trial implemented with a multi-resource utility company, we test the impact of a social information campaign to nudge water conservation over two years. We find that the water nudge significantly decreases water and electricity usage, but not gas. The effect is driven by customers who do not receive nudges targeting the other resources. Additional nudges have diminishing effects on resource savings, but not satisfaction: customers receiving a single or multiple reports are significantly less likely to deactivate their gas and electricity contracts. The results have important implications for designing policy interventions and business strategies to engage customers toward sustainable practices.