Evaluating the Carrot Rewards App, a Population-Level Incentive-Based Intervention Promoting Step Counts Across Two Canadian Provinces: Quasi-Experimental Study

Abstract

BackgroundThe Carrot Rewards app was developed as part of an innovative public-private partnership to reward Canadians with loyalty points, exchangeable for retail goods, travel rewards, and groceries for engaging in healthy behaviors such as walking.ObjectiveThis study examined whether a multicomponent intervention including goal setting, graded tasks, biofeedback, and very small incentives tied to daily step goal achievement (assessed by built-in smartphone accelerometers) could increase physical activity in two Canadian provinces, British Columbia (BC) and Newfoundland and Labrador (NL).MethodsThis 12-week, quasi-experimental (single group pre-post) study included 78,882 participants; 44.39% (35,014/78,882) enrolled in the Carrot Rewards “Steps” walking program during the recruitment period (June 13–July 10, 2016). During the 2-week baseline (or “run-in”) period, we calculated participants’ mean steps per day. Thereafter, participants earned incentives in the form of loyalty points (worth Can $0.04 ) every day they reached their personalized daily step goal (ie, baseline mean+1000 steps=first daily step goal level). Participants earned additional points (Can $0.40) for meeting their step goal 10+ nonconsecutive times in a 14-day period (called a “Step Up Challenge”). Participants could earn up to Can $5.00 during the 12-week evaluation period. Upon meeting the 10-day contingency, participants could increase their daily goal by 500 steps, aiming to gradually increase the daily step number by 3000. Only participants with ≥5 valid days (days with step counts: 1000-40,000) during the baseline period were included in the analysis (n=32,229).The primary study outcome was mean steps per day (by week), analyzed using linear mixed-effects models.ResultsThe mean age of 32,229 participants with valid baseline data was 33.7 (SD 11.6) years; 66.11% (21,306/32,229) were female. The mean daily step count at baseline was 6511.22. Over half of users (16,336/32,229, 50.69%) were categorized as “physically inactive,” accumulating <5000 daily steps at baseline. Results from mixed-effects models revealed statistically significant increases in mean daily step counts when comparing baseline with each study week (P<.001). Compared with baseline, participants walked 115.70 more steps (95% CI 74.59 to 156.81; P<.001) at study week 12. BC and NL users classified as “high engagers” (app engagement above sample median; 15,511/32,229, 48.13%) walked 738.70 (95% CI 673.81 to 803.54; P<.001) and 346.00 (95% CI 239.26 to 452.74; P<.001) more steps, respectively. Physically inactive, high engagers (7022/32,229, 21.08%) averaged an increase of 1224.66 steps per day (95% CI 1160.69 to 1288.63; P<.001). Effect sizes were modest.ConclusionsProviding very small but immediate rewards for personalized daily step goal achievement as part of a multicomponent intervention increased daily step counts on a population scale, especially for physically inactive individuals and individuals who engaged more with the walking program. Positive effects in both BC...

Commercial app use linked with sustained physical activity in two Canadian provinces: a 12-month quasi-experimental study

“…1) provided very small incentives for individualized daily step goal achievements. A three-month "Steps" evaluation was published in 2018 [30]. In this quasi-experimental study of users living in two Canadian provinces, Mitchell et al (2018) found average daily step count increased by 5% between baseline and the three-month assessment (115.70 steps; P < .001).…”

“…A three-month "Steps" evaluation was published in 2018 [30]. In this quasi-experimental study of users living in two Canadian provinces, Mitchell et al (2018) found average daily step count increased by 5% between baseline and the three-month assessment (115.70 steps; P < .001). A more pronounced 32% increase was observed among highly engaged, physically inactive users (1224.66 steps; P < .001).…”

Adding Team-Based Financial Incentives to the Carrot Rewards App Increases Daily Step Count on a Population Scale: A 24-Week Matched Pairs Study

“…This aligns with a growing but still limited (to a small number of RCTs) evidence base suggesting that app exposure is paramount and that greater engagement may produce greater effects. [10][11][12]32 Limitations This study was not without limitations. The quasi-experimental design, for instance, makes it di cult to conclude with con dence that the Carrot Rewards STC feature caused an increase in PA. To increase internal validity in this real-world public health intervention context, we matched experimental participants with similar controls, used three main analytic approaches to address our primary objective and conducted two sensitivity analyses.…”

“…50 With nearly half of the Carrot Rewards users in general accumulating less than 5,000 steps per day, a mere 500 to 1,000 step increase from baseline values could have broad implications. 12 In fact, a recent 12 month analysis of the Carrot Rewards app suggests approximately 100,000 Canadians (or 0.3% of the Canadian population) moved up from the "physically inactive" category to the "moderately active" (5,000 to 7,500 steps per day). 34 Similar studies…”

“…33 One of the stated objectives of the initiative was to conduct rigorous evaluations of the app intervention, including the impact of new features. 12,34 In March 2018, Carrot Rewards launched a new social feature called 'Step Together Challenges' (STCs) to complement their existing walking program (called 'Steps') where individualized daily step goal achievements were rewarded with very small incentives ($0.04 CAD per day). STCs allowed users to invite a friend from their existing social network to participate in a collaborative walking challenge for bonus incentives ($0.40 CAD per week).…”