- Live feedback (provided during the activity) leads to considerably larger savings than outcome feedback with minimal delay

- Outcome takes a while to unfold its effect on resource consumption, whereas the impact of live feedback is immediate and stable over the study period

- The results challenge existing theory and provide novel insights about the behavioral mechanisms of feedback

Feedback interventions have proven to be an effective instrument for behavior change. Prior research states that feedback should be provided in a “timely” manner. Laboratory studies show that, at least in complex tasks, even minimal feedback delays may lead to disastrous consequences. On the other hand, timely feedback may require costly infrastructure that allows for the transmission and storage of large data volumes and increases risks regarding privacy concerns and information overload.

In a two-month randomized controlled trial with 517 Swiss households, we evaluate the impact of two types of activity-specific feedback: Live feedback (provided during the activity) and outcome feedback that is provided with minimal delay right after the activity. More precisely, participants receive feedback on their resource use in the shower. We measure the energy use per shower as dependent variable and explore the underlying behavioral mechanisms.

- Both types of activity-specific feedback induce large savings. Outcome feedback reduces energy use for the target behavior by 14%. With a 23% treatment effect, the impact of live feedback is even larger.

- We provide empirical evidence that contradicts prior research that a) attributes the importance of timeliness to task complexity, b) attributes the impact to the updating of prior perception errors, and c) media richness theory.