How many days of global positioning system (GPS) monitoring do you need to measure activity space environments in health research?

Abstract

This study examined the number of days of global positioning system (GPS) monitoring needed to measure attributes of an individual's routine activity space. Multiple alternative activity space representations (cumulative, mean daily), measures (kernel density, route buffer, convex hull), and attributes (area size, supermarkets, fast food restaurants, parks) were examined. Results suggested wide variability in required GPS days to obtain valid estimates of activity space attributes (1-23 days). In general, fewer days were needed for mean daily activity space representations, kernel density measures, and densities of environmental exposures (vs. counts). While kernel density measures reliably estimated between-person differences in attributes after just a few days, most variability in environmental attributes for convex hull and route buffer measures was within-person. Based on these results, a minimum of 14 days of valid GPS data is recommended to measure activity spaces.

Obesity and the Built Environment: A Reappraisal

“…Measuring and quantifying human exposure to the neighborhood BE have been accomplished in a variety of ways . Current studies on obesity and the BE owe much to the development of geographic information systems (GIS) and the widespread use of global positioning system (GPS) devices . Elements of the neighborhood BE tend to be categorized into the food environment and the physical activity (PA) environment .…”

“…Accordingly, such BE measurement tools have become increasingly more sophisticated using wearable GPS devices, often augmented with travel diaries, travel logs, Google street views, or other mobile technologies . These approaches allow the capture of near instantaneous measures of exposure to the BE not only around the home location but also at work, school, and along travel routes . Mobile technologies have become increasingly atomized, allowing researchers to capture the minutiae of daily activities in time and space, sometimes at time resolutions of 10 seconds or less.…”

A statistical framework for measuring the temporal stability of human mobility patterns

“…The previous empirical study [43] that focused on assessing the duration of GPS studies is based on data collected over 30 days. By using our new statistical methods and GPS data collected over a much longer period of time, we determined that GPS monitoring needs to be done for at least 15 weeks which represents a minimum study duration about 7 times longer than the 14 days minimum duration recommended in [43]. We also put forward the idea that the duration of GPS studies should be assessed by demographic groups.…”

“…Previous work [43] on the temporal stability of spatiotemporal trajectories has used the mean absolute percentage error (MAPE) which is the average of the APE across study participants:…”

Examen rapide des études spatialisées traitant des lieux d’activité physique et de sédentarité des enfants et des adultes

“…L'utilisation de données GPS superposées à celles de SIG permet de déter miner de façon plus précise la localisation du mouvement, mais la qualité des don nées issues des SIG est variable et peut même introduire une source de biais de mesure 87 . Les conclusions tirées de la litté rature ont également permis d'établir que de 12 à 14 jours de surveillance sont néces saires pour obtenir des estimations fiables de l'AP, et que le temps passé au domicile ou dans un environnement commercial exige une période de surveillance considé rable (supérieure à 19 jours) 88,89 . La majorité des études prises en compte ont enregistré les mouvements sur 7 jours, bon nombre d'entre elles ne comptant que 4 jours de données valides.…”