One thing leads to another: Evidence on the scope and persistence of behavioral spillovers

Abstract

Evaluations of economic interventions usually focus on one target behavior. This study extends the evaluation scope to multiple untargeted behaviors. We evaluate a hot water saving intervention in a natural field experiment. Despite an exclusive focus on hot water, the intervention changes multiple behaviors. We find a 5.6 percent reduction in room heating energy consumption that persists one year after the intervention. In addition, households save cold water for dishwasher use and toilet flushing several months after the intervention. The remarkable persistence of these spillover effects is consistent with a mechanism of cognitive dissonance, where behavior change reinforces future behavior change. We show that the room heating spillover has important welfare implications. The intervention does not improve welfare when only the target effect on hot water is considered. Taking the spillover on room heating into account, the welfare effect of the intervention turns decisively positive.

Keywords: Behavioral spillover, randomized controlled trial, water consumption, energy consumption, welfare

JEL Classification: C93, D12, Q50