Data collection and measures
depression, anxiety, sunburn, sunburns
Due to the COVID-19 pandemic, all study procedures were conducted remotely. Study measures were collected via online surveys and the Shade device. Participants were mailed their device, training materials, and mobile app access at the time of randomization. Participants were asked to wear the device and sync it with the mobile app every day for 12 weeks. The study coordinator monitored device use of all participants and contacted participants who did not use their device or sync the app data on more than 3 days in any given week to determine barriers and encourage use. We used a weekly $100 raffle-drawing incentive to promote adherence. Almost half (40%) of participants unexpectedly experienced broken straps or device malfunction during the study. Damaged or defective devices were promptly replaced; nevertheless, many participants were without a functioning device for approximately 5–10 days during the study.Self-administered questionnaire data were collected at baseline, week 4, week 8, and week 12 (end of intervention), as well as week 64 (end of the summer, one year after intervention completion) to assess potential continued behavior change.The primary outcome was a composite measure of sun protection behaviors (sun habit score) at the end of the intervention period (12-week survey) [Secondary outcomes included a) sunburns (the proportions of individuals who self-reported at least one red or painful sunburn in the past 3 months at the 12-week survey) [We measured self-reported physical activity, depression, and anxiety to examine potential unintended negative consequences of the intervention. Physical activity was measured using the Godin Leisure-Time Exercise Questionnaire [