Tracking human activity in real time and at fine spatial scale is particularly valuable during episodes such as the COVID-19 pandemic In this paper, we discuss the suitability of smartphone data for quantifying movement and social contact These data cover broad sections of the US population and exhibit pre-pandemic patterns similar to conventional survey data We develop and make publicly available a location exposure index that summarizes county-to-county movements and a device exposure index that quantifies social contact within venues We also investigate the reliability of smartphone movement data during the pandemic © 2021 Elsevier Inc
JUE Insight: Measuring movement and social contact with smartphone data: a real-time application to COVID-19