Can commitment contracts boost participation in public health programmes?

Commitment devices aim to help people make better choices in the face of their inherent biases: they are voluntary strategies aimed at changing behaviours by introducing costs to your current self, to bring about gains for your future self. Adherence to a structured health intervention is an important part of achieving health goals, and may be improved by commitment devices designed to keep people on track with their health goals. A field experiment set in a public weight management programme tests whether a personal commitment device in the form of a contract with oneself, which relies solely on self-reputation costs, can raise weekly participation and completion of the programme. Results suggest the commitment contract can significantly improve attendance (p = 0.05) and completion rates (p = 0.032), with some suggestive evidence that the contract works especially well for people with more myopic health attitudes. Findings also suggest the commitment contract can substitute for, but does not necessarily add to, wider commitment features in the health programme; raising new questions around threshold effects and the theory underlying commitment devices.