The Limits of Simple Implementation Intentions: Evidence from a Field Experiment on Making Plans to Exercise
Recent large-scale randomized experiments find that helping people form implementation intentions by asking when and where they plan to act increases one-time actions, such as vaccinations, preventative screenings and voting. We investigate the effect of a simple scalable planning intervention on a repeated behavior using a randomized design involving 877 subjects at a private gym. Subjects were randomized into i) a treatment group who selected the days and times they intended to attend the gym over the next two weeks or ii) a control group who instead recorded their days of exercise in the prior two weeks. In contrast to recent studies, we find that the planning intervention did not have a positive effect on behavior and observe a tightly estimated null effect. This lack of effect is despite the fact that the majority of subjects believe that planning is helpful and despite clear evidence that they engaged with the planning process.
We are grateful for funding from the NIH and the outstanding research assistant work of Jacob Adamcik and Chang Lee. We thank conference participants at Advances with Field Experiments for helpful comments and suggestions. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.
Mariana Carrera & Heather Royer & Mark Stehr & Justin Sydnor & Dmitry Taubinsky, 2018. "The limits of simple implementation intentions: Evidence from a field experiment on making plans to exercise," Journal of Health Economics, vol 62, pages 95-104. citation courtesy of