Framing Financial Incentives to Increase Physical Activity Among Overweight and Obese Adults: A Randomized, Controlled Trial

Abstract

Background: Financial incentive designs to increase physical activity have not been well-examined.

Objective: To test the effectiveness of 3 methods to frame financial incentives to increase physical activity among overweight and obese adults.

Design: Randomized, controlled trial. (ClinicalTrials.gov: NCT 02030119).

Setting: University of Pennsylvania.

Participants: 281 adult employees (body mass index ≥27 kg/m2).

Intervention: 13-week intervention. Participants had a goal of 7000 steps per day and were randomly assigned to a control group with daily feedback or 1 of 3 financial incentive programs with daily feedback: a gain incentive ($1.40 given each day the goal was achieved), lottery incentive (daily eligibility [expected value approximately $1.40] if goal was achieved), or loss incentive ($42 allocated monthly upfront and $1.40 removed each day the goal was not achieved). Participants were followed for another 13 weeks with daily performance feedback but no incentives.

Measurements: Primary outcome was the mean proportion of participant-days that the 7000-step goal was achieved during the intervention. Secondary outcomes included the mean proportion of participant-days achieving the goal during follow-up and the mean daily steps during intervention and follow-up.

Results: The mean proportion of participant-days achieving the goal was 0.30 (95% CI, 0.22 to 0.37) in the control group, 0.35 (CI, 0.28 to 0.42) in the gain-incentive group, 0.36 (CI, 0.29 to 0.43) in the lottery-incentive group, and 0.45 (CI, 0.38 to 0.52) in the loss-incentive group. In adjusted analyses, only the loss-incentive group had a significantly greater mean proportion of participant-days achieving the goal than control (adjusted difference, 0.16 [CI, 0.06 to 0.26]; P = 0.001), but the adjusted difference in mean daily steps was not significant (861 [CI, 24 to 1746]; P = 0.056). During follow-up, daily steps decreased for all incentive groups and were not different from control.

Limitation: Single employer.

Conclusion: Financial incentives framed as a loss were most effective for achieving physical activity goals.

Primary funding source: National Institute on Aging.

Trial registration: ClinicalTrials.gov NCT02030119.

Figure 1

Study flow diagram. One participant randomly assigned to the gain-incentive group was later found to be ineligible due to previous enrollment in another physical activity study. One participant randomly assigned to the lottery-incentive group switched to a phone that was not eligible for use before the study began and therefore did not receive the intervention.

Figure 2

Weekly unadjusted mean proportion of participant-days achieving the 7000-step goal.