Intended for healthcare professionals


Commitment contracts as a way to health

BMJ 2012; 344 doi: (Published 30 January 2012) Cite this as: BMJ 2012;344:e522
  1. Scott D Halpern, assistant professor of medicine 1234,
  2. David A Asch, professor of medicine12356,
  3. Kevin G Volpp, professor of medicine1256
  1. 1Leonard Davis Institute of Health Economics, Center for Health Incentives and Behavioral Economics, University of Pennsylvania
  2. 2Department of Medicine, University of Pennsylvania, 423 Guardian Drive, Philadelphia, PA 19104-6021, USA
  3. 3Center for Bioethics, University of Pennsylvania
  4. 4Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania
  5. 5VA Center for Health Equity Research and Promotion, University of Pennsylvania
  6. 6Department of Health Care Management, Wharton School, University of Pennsylvania
  1. Correspondence to: S D Halpern shalpern{at}
  • Accepted 5 December 2011

Commitment contracts, whereby people deposit money that they receive back only if they succeed, have substantial conceptual appeal as a method of changing health behaviour. Scott Halpern, David Asch, and Kevin Volpp examine the evidence behind them and find many unanswered questions

Much illness stems from poor health behaviours. But changing behaviours is difficult, particularly when immediate desires must be sacrificed to achieve future benefits,1 as when people try to quit smoking, eat less, or exercise more. To overcome these challenges, corporate ventures such as and are banking, quite literally, on commitment contracts, offering the millions of people who struggle to lose weight or take their medicines more regularly the opportunity to deposit money that they will receive back only if they succeed. Grounded in behavioural economic theory,2 commitment contracts bring a risk of loss into the present, where the temptations also lie, and augment motivation to succeed. They potentially offer an efficient mechanism of behaviour change because people generally are more motivated to avoid losses than they are to achieve similarly sized gains.3

Although new to health promotion, the idea of making voluntary commitments that restrict future options has a rich history. Cortes scuttled his ships to enhance his soldiers’ commitments to overthrowing the Aztec empire. Odysseus lashed himself to his ship’s mast so he could hear the song of the Sirens but not be tempted to throw himself overboard. And for more than a century, people have saved money in Christmas club accounts that provide little or no interest and charge fees to prevent early withdrawals, despite the widespread availability of penalty-free savings accounts with higher interest rates. Indeed, recent evidence shows that some people use commitment contracts to help them save money,4 complete homework assignments on time,5 and limit their …

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