@Article{info:doi/10.2196/mhealth.9912,
author="Mitchell, Marc
and White, Lauren
and Lau, Erica
and Leahey, Tricia
and Adams, Marc A
and Faulkner, Guy",
title="Evaluating the Carrot Rewards App, a Population-Level Incentive-Based Intervention Promoting Step Counts Across Two Canadian Provinces: Quasi-Experimental Study",
journal="JMIR Mhealth Uhealth",
year="2018",
month="Sep",
day="20",
volume="6",
number="9",
pages="e178",
keywords="behavioral economics; financial health incentives; mHealth; mobile phone; physical activity; public health",
abstract="Background: The 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. Objective: This 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). Methods: This 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. Results: The 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. Conclusions: Providing 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 and NL provide evidence of replicability. ",
issn="2291-5222",
doi="10.2196/mhealth.9912",
url="http://mhealth.jmir.org/2018/9/e178/",
url="https://doi.org/10.2196/mhealth.9912",
url="http://www.ncbi.nlm.nih.gov/pubmed/30148712"
}