Background: More than half of adults in the United States do not attain the minimum recommended level of physical activity to achieve health benefits. The optimal design of financial incentives to promote physical activity is unknown.
Objective: To compare the effectiveness of individual versus team-based financial incentives to increase physical activity.
Design: Randomized, controlled trial comparing three interventions to control.
Participants: Three hundred and four adult employees from an organization in Philadelphia formed 76 four-member teams.
Interventions: All participants received daily feedback on performance towards achieving a daily 7000 step goal during the intervention (weeks 1- 13) and follow-up (weeks 14- 26) periods. The control arm received no other intervention. In the three financial incentive arms, drawings were held in which one team was selected as the winner every other day during the 13-week intervention. A participant on a winning team was eligible as follows: $50 if he or she met the goal (individual incentive), $50 only if all four team members met the goal (team incentive), or $20 if he or she met the goal individually and $10 more for each of three teammates that also met the goal (combined incentive).
Main measures: Mean proportion of participant-days achieving the 7000 step goal during the intervention.
Key results: Compared to the control group during the intervention period, the mean proportion achieving the 7000 step goal was significantly greater for the combined incentive (0.35 vs. 0.18, difference: 0.17, 95 % confidence interval [CI]: 0.07-0.28, p <0.001) but not for the individual incentive (0.25 vs 0.18, difference: 0.08, 95 % CI: -0.02-0.18, p = 0.13) or the team incentive (0.17 vs 0.18, difference: -0.003, 95 % CI: -0.11-0.10, p = 0.96). The combined incentive arm participants also achieved the goal at significantly greater rates than the team incentive (0.35 vs. 0.17, difference: 0.18, 95 % CI: 0.08-0.28, p < 0.001), but not the individual incentive (0.35 vs. 0.25, difference: 0.10, 95 % CI: -0.001-0.19, p = 0.05). Only the combined incentive had greater mean daily steps than control (difference: 1446, 95 % CI: 448-2444, p ≤ 0.005). There were no significant differences between arms during the follow-up period (weeks 14- 26).
Conclusions: Financial incentives rewarded for a combination of individual and team performance were most effective for increasing physical activity.
Trial registration: Clinicaltrials.gov identifier: NCT02001194.
Keywords: behavioral economics; connected health; financial incentives; physical activity; smartphones; step counts; teams.