The feasibility of using consumer-level activity trackers in population monitoring of physical activity

Abstract

Consumer-level activity trackers can potentially be used for population monitoring of physical activity, without suffering from the recall and social desirability bias that occur in self-report and at lower costs and effort compared to research-grade devices. However, other drawbacks may be at play when using personal activity trackers. The current study compares response, representativeness and measurement quality of con- sumer-level activity trackers to a research-grade accelerometer (ActivPAL) and self-report (the SQUASH survey). The study existed of a questionnaire on physical activity, possession and usage of a personal activ- ity tracker and willingness to share data or wear a research-grade device. Subsequently, a smaller follow-up study was conducted in which respondents wore an ActivPAL and their own personal tracker to allow com- parison of the different methods. The results showed a loss of respondents in each step of the process. Addi- tionally, the representativeness of the response was influenced by both demographics and physical activity level, introducing nonresponse bias. The measurements of personal trackers had a decent agreement with the ActivPAL for number of minutes MVPA and steps, while both objective measures differed substantially from self-report on all indicators. It is concluded that consumer-level trackers are not a full replacement for self-report in large-scale studies for estimation of the exact physical activity level of a population due to representation and measurement issues, but could be used, possibly together with research-grade devices, to supplement or calibrate survey results. More research to identify and lower the barriers for respondents to participate in research with activity trackers is warranted.