Tie your money to your commitment — but first ask if you are willing to pay

If you want to push yourself to follow through, you can collect a bonus when you do it, or you can pay a deposit first and get it back plus a bonus only if you do it. Among people willing to join both, those who paid the deposit succeeded 13 percentage points more often. But only 13.7% were willing to pay a deposit, while 90% were willing to take the bonus, so a deposit only works for people willing to stake the money.

Benefit

A randomized trial of 2538 people in the United States randomly assigned employees and their family and friends to 4 incentive plans or to usual care. The reward type (about 800 dollars if you succeed) had an acceptance rate of 90.0%. The deposit type (pay 150 dollars first, plus a 650 dollar reward) had 13.7%. Sustained quit rates at 6 months: the 4 incentive plans were between 9.4% and 16.0%, and usual care was 6.0%. The reward type was 15.7%, and the deposit type was 10.2%. But counting only the 13.7% of people willing to join both of the 2, the deposit type's quit rate at 6 months was 13.2 percentage points higher than the reward type (95% CI 3.1 to 22.8, which is the confidence range).

Notes

This trial measured quitting smoking. Moving it to writing a paper, exercising, and similar tasks is an inference, so the benefit size is marked moderate. When you choose a plan, first look at whether you will actually use it, not at which one is more effective. A method most people will not accept, however strong the effect, does nothing for those people. So first pick the kind you are willing to accept. Staking a smaller amount is still better than staking nothing. How to quit smoking itself is in section 2, item 3 (medicine for quitting smoking).

Sources · 1

1. Halpern SD, French B, Small DS, et al. (2015). Randomized trial of four financial-incentive programs for smoking cessation. New England Journal of Medicine, 372(22), 2108–2117. doi.org/10.1056/NEJMoa1414293