Opportunity 

Physical activity is associated with many health benefits, including reduced rates of cardiovascular disease, diabetes, hypertension, and obesity. However, more than 50 percent of adults in the United States don't achieve enough regular physical activity to obtain such benefits. 

Intervention 

We designed a six-month randomized controlled trial to test the effect of lottery-based financial incentives in increasing physical activity. We partnered with the University of Pennsylvania Human Resources Department and enrolled 209 overweight and obese employees to participate in the study.  

Participants were given a goal of achieving 7,000 steps per day and were randomly assigned to a control group or one of three different lottery-based incentive arms. Participants in the simple lottery arm had a 1 in 4 chance of winning $5. Those in the jackpot arm had a 1 in 400 chance of winning $500, and those in the combined lottery arm had an 18 percent chance of winning $5 and a 1 percent chance of winning $50.  

Participants in all incentive arms received financial incentives for 13 weeks and were subsequently followed for 13 weeks without incentives. All participants tracked activity using their smartphones.   

Impact 

In the simple and jackpot lottery arms, there was no difference from the control. However, the combined lottery proved effective at increasing physical activity, with 38 percent of participants achieving 7,000 steps per day compared to 26 percent of participants in the control arm, a 12 percentage point increase.