Nudges versus prices: Lessons and challenges from a water-savings program

This study evaluates the effects of two exogenous interventions targeting residential consumers using both pecuniary and nonpecuniary incentives, with the potential of increasing the moral and monetary costs of water use. The first intervention provided households with personalized reports including normative information regarding household water use compared with neighbors. The second intervention consisted of an exogenous change in water tariffs. The timing of the interventions provides a unique opportunity to separately assess both the individual and combined effects of each policy instrument. The empirical analysis was conducted on the same sample households assessed in the field experiment by Jaime and Carlsson (2018), whose behavior was followed one year after implementation. The results reveal that both nonpecuniary and pecuniary incentives significantly reduce water use when each instrument is applied separately, with the change in tariffs generating larger reductions in water use, compared with information provision, at 11% vs. 7%, respectively. However, the effectiveness of the combined policy depends on the setting of implementation. While the differentiated effects of the social information campaign associated with the change in tariffs suggest this policy remains effective, the evidence also suggests potential crowding-out effects arising upon the introduction of the new tariff regime. The largest reductions in water use are achieved when the instruments are jointly implemented. Findings shed light on the importance of accurately defining the timing and order of the interventions to maximize their impact on resource conservation.