Complementarities in Behavioral Interventions: Evidence from a Field Experiment on Energy Conservation

Behavioral policy often aims at overcoming barriers like imperfect information or limited attention that cause suboptimal consumer decisions. We argue that when multiple barriers are present, it may be important to overcome them all at the same time, as intervention strategies eliminating only a single barrier can be undermined by the remaining barriers. Thus, behavioral interventions that are tailored towards addressing different barriers each can be complements, in the sense that each intervention is more effective in conjunction with the other(s) than in isolation. We conduct a three-month randomized field experiment on energy conservation in a resource-intensive everyday activity, using two different interventions, home energy reports and real-time feedback, which target information and attention barriers to different degrees, respectively. Crucially, we evaluate both the combined intervention as well as each intervention in isolation.

Home energy reports in isolation fail to reduce energy use despite achieving significant knowledge gains, whereas real-time feedback in isolation induces considerable conservation effects. Strikingly, combining both interventions boosts these effects by over 50 percent, thus showcasing how barrier multiplicity can generate complementarities in behavioral interventions.