Persistence: How Treatment Effects Persist After Interventions Stop

Interventions intended to change people’s behavior are ubiquitous in modern society. Some interventions produce changes in behavior that persist even after the interventions are discontinued, while other interventions generate only short-term behavior changes that disappear once the interventions stop. The framework presented here guides understanding of why and how behavior changes (treatment effects) persist after interventions (treatments) are discontinued. Four persistence pathways explain how persistent treatment effects may arise: building psychological habits, changing what and how people think, changing future costs, and harnessing external reinforcement. Each pathway is illustrated by describing how the pathway may have contributed to the persistent treatment effects produced by a widely used energy-efficiency intervention conducted by the energy-efficiency company OPOWER. Different conditions may make each pathway more or less likely to generate persistent treatment effects in the world. Finally, policymakers might develop more persistent interventions by leveraging each pathway.